Merge: the advice tap points both ways

Claude-Session: https://claude.ai/code/session_01KGACAtTPjvZ2PipDZ5qD99

internal/auth/pairlang_test.go

@@ -180,14 +180,17 @@ func TestDirectionRoundTrip(t *testing.T) {
 	}
 }
 
-// The refusal this axis exists to make: a pair with no word list cannot be
-// learned toward, however good its langpack is. fr, es and pt-PT all have copy,
-// voices and spelling dictionaries — and nothing that could segment a sentence
-// or read from that language into English, which is what a learner needs.
+// The refusal this axis exists to make: a pair with no learner-side data cannot
+// be learned toward, however good its langpack is. fr and es have copy, voices
+// and spelling dictionaries, and no `learner` block in their packs to offer the
+// choice with — so the server keeps saying no until one is written.
+//
+// pt-PT is deliberately no longer in this list; see TestLearnerDirectionForPtPT
+// below and the argument in `learnerPairs`.
 func TestLearnerDirectionRefusedForPairsWithoutData(t *testing.T) {
 	_, users, _ := newStores(t)
 
-	for _, lang := range []string{"pt-PT", "fr", "es"} {
+	for _, lang := range []string{"fr", "es"} {
 		if err := users.SetPair("bob", lang, DirectionLearningEn); err != nil {
 			t.Fatalf("set %s: %v", lang, err)
 		}
@@ -201,6 +204,37 @@ func TestLearnerDirectionRefusedForPairsWithoutData(t *testing.T) {
 	}
 }
 
+// The other direction of that same rule, and the one a native English speaker
+// writing Portuguese depends on.
+//
+// This is not only a settings toggle: `direction` is what decides which language
+// Petal *explains* in (see suggestions.targetFor), so an account that cannot
+// reach learning_pair gets its Portuguese annotated in Portuguese with no way to
+// ask for English. Pinned in both directions — the move must take, and it must
+// still be there when the account is read back.
+func TestLearnerDirectionForPtPT(t *testing.T) {
+	_, users, _ := newStores(t)
+
+	if err := users.SetPair("bob", "pt-PT", DirectionLearningEn); err != nil {
+		t.Fatalf("set pt-PT: %v", err)
+	}
+	if w := patchMe(t, users, "bob", `{"direction":"learning_pair"}`); w.Code != http.StatusOK {
+		t.Fatalf("status = %d (%s), want 200", w.Code, w.Body.String())
+	}
+	u, _ := users.Get("bob")
+	if u.Direction != DirectionLearningPair || u.PairLang != "pt-PT" {
+		t.Fatalf("account = %+v, want pt-PT learning_pair", u)
+	}
+
+	// And it can be turned back, the same as zh.
+	if w := patchMe(t, users, "bob", `{"direction":"learning_en"}`); w.Code != http.StatusOK {
+		t.Fatalf("turn back: status = %d (%s)", w.Code, w.Body.String())
+	}
+	if u, _ := users.Get("bob"); u.Direction != DirectionLearningEn {
+		t.Fatalf("direction = %q after turning back", u.Direction)
+	}
+}
+
 // The two-field combination the handler validates as one decision. An account
 // already learning Chinese that asks only to change pair is asking for a state
 // neither field names on its own — French with segmentation — and it must not

internal/auth/users.go

@@ -104,19 +104,34 @@ const (
 // The pairs whose *learner* direction Petal can actually serve, which is a
 // narrower thing than a shipped pair and narrower again than a langpack.
 //
-// Turning a pair around needs data no langpack carries: a word list to segment
-// with, and a dictionary that reads from the pair language into English. Chinese
-// has both as of Phase 26 (CC-CEDICT + jieba); French, Spanish and Portuguese
-// have neither yet, and — unlike a missing pack, which leaves a writer looking
-// at copy she cannot read — a missing word list would leave her looking at an
-// editor that silently does nothing when she hovers. Both are bad; only one is
-// legible as a bug. So the server refuses, for the same reason and by the same
-// mechanism as `shippedPairs`.
+// Turning a pair around needs data no langpack carries: a way to find word
+// boundaries, and a dictionary that reads from the pair language into English. A
+// pair missing either would leave a writer looking at an editor that silently
+// does nothing when she hovers — worse than a missing pack, which at least reads
+// as a bug rather than as an absence. So the server refuses, for the same reason
+// and by the same mechanism as `shippedPairs`.
 //
-// This list is expected to grow one pair at a time and never to be inferred:
-// segmentation is a property of a writing system, and there is no rule that
-// derives "has a word list" from a language code.
-var learnerPairs = []string{"zh"}
+// Chinese has both as of Phase 26 (CC-CEDICT + jieba). Portuguese turns out to
+// have both as well, and the original note here — "French, Spanish and
+// Portuguese have neither" — was written one phase too early to see it:
+//
+//   - Word boundaries are spaces. The megabyte word list jieba needs is a
+//     property of a writing system that doesn't use them, not a debt every pair
+//     owes; a Latin-script pair needs nothing loaded to be segmented.
+//   - The dictionary arrived with dict.db, which reads pt→en as readily as
+//     en→pt (see lexicon.dreamProvider.reverse). The reverse lookup the hover
+//     and the word card need is already there and already answering.
+//
+// So the pair a native English speaker learning Portuguese needs is real, and
+// what was actually blocking it was this list. French and Spanish clear the same
+// two bars through the same dict.db; they are held back only by their packs
+// carrying no `learner` copy yet (see Pack.learner), which is a translation
+// question rather than a data one.
+//
+// This list is still expected to grow one pair at a time and never to be
+// inferred: segmentation is a property of a writing system, and there is no rule
+// that derives "has a word list" from a language code.
+var learnerPairs = []string{"zh", "pt-PT"}
 
 // SupportsLearnerDirection reports whether a pair can be turned around.
 func SupportsLearnerDirection(lang string) bool {

internal/db/db.go

@@ -589,6 +589,55 @@ CREATE INDEX idx_suggestions_resolved ON suggestions(status, resolved_at);
 			stmt: `
 ALTER TABLE users ADD COLUMN direction TEXT NOT NULL DEFAULT 'learning_en'
     CHECK(direction IN ('learning_en','learning_pair'));
+`,
+		},
+		{
+			// Which language this document is written in — 'en' or 'pair'.
+			//
+			// It is stored, rather than recomputed per pass and forgotten, for one
+			// reason: the verdict has hysteresis (see suggestions/doclang.go). A
+			// bilingual document sits between the two thresholds, and "whatever it
+			// was last time" is only an answer if last time was written down. Without
+			// the column a mixed paragraph would alternate its cards' language
+			// between passes.
+			//
+			// 'pair' rather than a language code, deliberately. Which language "pair"
+			// names is the owner's users.pair_lang, so changing her pair re-reads her
+			// documents instead of stranding a stale language name on every one of
+			// them.
+			//
+			// Empty is the backfill and means English: every document that exists
+			// today was written by a Mandarin native practising English, and English
+			// is what every surface assumed before this phase.
+			name: "0017_document_lang",
+			stmt: `
+ALTER TABLE documents ADD COLUMN doc_lang TEXT NOT NULL DEFAULT ''
+    CHECK(doc_lang IN ('', 'en', 'pair'));
+`,
+		},
+		{
+			// Which language a garden card is in — the same '' | 'en' | 'pair'
+			// vocabulary as documents.doc_lang, and set from it: a word is captured
+			// (or a phrase planted) out of a document, so the document's verdict is
+			// the card's language. A card with no document keeps '', which reads as
+			// English like every other empty here.
+			//
+			// The garden needed this the moment a document could be written in her
+			// own language. Before Phase 28 every card was English by construction;
+			// now a Portuguese lookup lands beside an English one with nothing to
+			// tell them apart, and two surfaces get it wrong without the tag — the
+			// review card's read-aloud (which would say a Portuguese word in a US
+			// English voice) and the panel, where a mixed garden is illegible.
+			//
+			// Every card is reviewed regardless. Filtering the queue to the half she
+			// is learning was the alternative and is wrong for the writer this is
+			// for: the words she met while writing Portuguese are still words she
+			// met, and a garden that quietly drops them is a garden that stops being
+			// a record of her reading.
+			name: "0018_vocab_lang",
+			stmt: `
+ALTER TABLE vocab_words ADD COLUMN lang TEXT NOT NULL DEFAULT ''
+    CHECK(lang IN ('', 'en', 'pair'));
 `,
 		},
 	}

internal/db/models.go

@@ -41,6 +41,11 @@ type Document struct {
 	ContentText string `json:"content_text"` // plain text for the LLM
 	Tone        string `json:"tone"`         // target writing tone; steers LLM advice
 	WordCount   int    `json:"word_count"`
+	// DocLang is which language this document is written in — '' | 'en' | 'pair'
+	// (migration 0017), written by the checkpoint pass and never by the client.
+	// It reaches the client read-only, for the one decision the client has to
+	// make on its own: which voice reads a selection aloud. '' means English.
+	DocLang   string    `json:"doc_lang"`
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 

internal/docs/handlers.go

@@ -225,13 +225,14 @@ func (h *Handler) fetch(userID, id string) (db.Document, error) {
 	var doc db.Document
 	err := h.DB.QueryRow(
 		`SELECT id, user_id, title, content, content_text, tone, word_count,
-		        created_at, updated_at, preserve_history
+		        created_at, updated_at, preserve_history, doc_lang
 		   FROM documents
 		  WHERE id = ? AND user_id = ?`,
 		id, userID,
 	).Scan(
 		&doc.ID, &doc.UserID, &doc.Title, &doc.Content, &doc.ContentText,
 		&doc.Tone, &doc.WordCount, &doc.CreatedAt, &doc.UpdatedAt, &doc.PreserveHistory,
+		&doc.DocLang,
 	)
 	return doc, err
 }

internal/lexicon/handlers.go

@@ -49,10 +49,19 @@ func (h *Handler) GlossRoutes() chi.Router {
 // It does not go through [Handler.providerFor], and that is not an oversight.
 // providerFor picks a dictionary by the writer's *pair*, to answer "what does
 // this English word mean in her language" — a question whose answer differs per
-// pair. This endpoint asks the opposite question of exactly one language, and
-// [auth.SupportsLearnerDirection] already guarantees that language is Chinese.
-// Routing it through the pair would add a database read per hover to choose
-// between one option and itself.
+// pair. This endpoint asks the opposite question of exactly one language: it
+// reads hanzi, and hanzi are Chinese whoever is looking them up. Routing it
+// through the pair would add a database read per hover to choose between one
+// option and itself.
+//
+// What no longer holds is the reason this used to give — that
+// [auth.SupportsLearnerDirection] guarantees the caller is on the zh pair. Since
+// Portuguese joined `learnerPairs` a learning_pair account may be Portuguese, so
+// the guarantee now comes from the *caller*: the client only ever asks this
+// route about a token its Chinese segmenter found, and that segmenter is loaded
+// only for the zh pair (see useSegmenter in App.tsx). A stray lookup is still
+// answered safely — a word the Chinese dictionary has never heard of is a 200
+// with empty lists, exactly like any other miss.
 func (h *Handler) HanziRoutes() chi.Router {
 	r := chi.NewRouter()
 	r.Get("/{word}", h.hanzi)

internal/llm/checkpoint.go

@@ -41,9 +41,9 @@ type checkpointResponse struct {
 // RunCheckpoint sends the grammar checkpoint and parses the JSON result. It
 // applies the latency-guard truncation and the checkpoint sampling parameters
 // from the spec.
-func RunCheckpoint(ctx context.Context, client LLMClient, contentText, tone string, _ Lang) ([]RawSuggestion, error) {
+func RunCheckpoint(ctx context.Context, client LLMClient, contentText, tone string, t Target) ([]RawSuggestion, error) {
 	raw, err := client.Complete(ctx, CompletionRequest{
-		Messages:          CheckpointMessages(TruncateDoc(contentText), tone),
+		Messages:          CheckpointMessages(TruncateDoc(contentText), tone, t),
 		MaxTokens:         checkpointMaxTokens,
 		Temperature:       0.3,
 		RepetitionPenalty: 1.15,

internal/llm/collocation.go

@@ -20,9 +20,9 @@ const CollocationInterval = 25 * time.Second
 // The tone argument is accepted for a uniform pass signature and passed through
 // to the prompt so a hint can prefer a register-appropriate pairing. `lang` is
 // the writer's pair language — the one each hint's short gloss is written in.
-func RunCollocation(ctx context.Context, client LLMClient, contentText, tone string, lang Lang) ([]RawSuggestion, error) {
+func RunCollocation(ctx context.Context, client LLMClient, contentText, tone string, t Target) ([]RawSuggestion, error) {
 	raw, err := client.Complete(ctx, CompletionRequest{
-		Messages:          CollocationMessages(contentText, tone, lang),
+		Messages:          CollocationMessages(contentText, tone, t),
 		MaxTokens:         2048,
 		Temperature:       0.3,
 		RepetitionPenalty: 1.15,

internal/llm/lang_test.go

@@ -31,7 +31,7 @@ func TestLangForFallsBackToDefault(t *testing.T) {
 func TestPromptsNameTheWritersLanguage(t *testing.T) {
 	pt := LangFor("pt-PT")
 
-	collocation := CollocationMessages("The rain was strong.", "casual", pt)[0].Content
+	collocation := CollocationMessages("The rain was strong.", "casual", EnglishTarget(pt))[0].Content
 	if !strings.Contains(collocation, "European Portuguese") {
 		t.Fatalf("collocation prompt doesn't ask for a pt-PT gloss:\n%s", collocation)
 	}
@@ -44,7 +44,7 @@ func TestPromptsNameTheWritersLanguage(t *testing.T) {
 		t.Fatalf("collocation prompt lost its tone guidance:\n%s", collocation)
 	}
 
-	translate := TranslateMessages("Try a shorter sentence here.", pt)[0].Content
+	translate := TranslateMessages("Try a shorter sentence here.", English, pt)[0].Content
 	if !strings.Contains(translate, "European Portuguese") || strings.Contains(translate, "Chinese") {
 		t.Fatalf("translate prompt targets the wrong language:\n%s", translate)
 	}
@@ -73,10 +73,10 @@ func TestPromptsNameTheWritersLanguage(t *testing.T) {
 func TestDefaultPairStillReadsAsBefore(t *testing.T) {
 	zh := LangFor("zh")
 
-	if got := CollocationMessages("x", "", zh)[0].Content; !strings.Contains(got, "Simplified Chinese (Mandarin) gloss in parentheses") {
+	if got := CollocationMessages("x", "", EnglishTarget(zh))[0].Content; !strings.Contains(got, "Simplified Chinese (Mandarin) gloss in parentheses") {
 		t.Fatalf("zh collocation gloss changed:\n%s", got)
 	}
-	if got := TranslateMessages("x", zh)[0].Content; !strings.Contains(got, "natural, friendly Simplified Chinese (Mandarin)") {
+	if got := TranslateMessages("x", English, zh)[0].Content; !strings.Contains(got, "natural, friendly Simplified Chinese (Mandarin)") {
 		t.Fatalf("zh translate target changed:\n%s", got)
 	}
 	if got := AskPetalSystemPrompt("a", "b", "c", "d", "e", zh); !strings.Contains(got, "为什么") {

internal/llm/prompts.go

@@ -45,11 +45,55 @@ func toneGuidance(tone string) string {
 		"be improved, prefer suggestions that fit that tone, and gently flag wording that clashes with it."
 }
 
+// pairCheckpointSystemPrompt is the grammar checkpoint for a document written in
+// the writer's own language rather than in English.
+//
+// It is a separate constant rather than a language clause appended to
+// checkpointSystemPrompt, because that prompt opens by naming the reader as an
+// ESL learner and asks for "common ESL patterns" — appending "and explain in
+// Portuguese" would hand the model two contradictory framings. Only the framing
+// differs; the JSON contract and the tone clause below it are the same
+// instructions in the same order, so the two prompts stay comparable.
+//
+// The "never translate" line is the one the model most wants to disobey: asked
+// to improve Portuguese while being an English writing assistant by training, it
+// will happily hand back an English rendering, which is a translation card
+// (Phase 25's `isTranslation`) and not a correction.
+const pairCheckpointSystemPrompt = `You are a warm, encouraging writing assistant. The person you are helping is ` +
+	`writing in %[1]s, and the text below is %[1]s. ` +
+	`Analyze it and identify up to 5 issues: grammar errors, unnatural phrasing, ` +
+	`incorrect idiom usage, or unclear sentences.
+
+Both "original" and "replacement" must be written in %[1]s. You are improving their %[1]s writing — ` +
+	`never translate it into English, and never suggest they write in English instead.
+Write every "explanation" in %[2]s.
+
+Be specific, friendly, and explain WHY each suggestion improves the writing.%[3]s
+
+Respond ONLY with valid JSON. No preamble, no markdown fences. Format:
+{
+  "suggestions": [
+    {
+      "original": "exact text from the document that needs fixing",
+      "replacement": "corrected version",
+      "explanation": "friendly one-sentence explanation",
+      "type": "grammar|phrasing|idiom|clarity"
+    }
+  ]
+}
+
+If the writing looks good, return: {"suggestions": []}`
+
 // CheckpointMessages builds the message array for a grammar checkpoint over the
-// given (already-truncated) document text, steered toward the document's tone.
-func CheckpointMessages(contentText, tone string) []Message {
+// given (already-truncated) document text, steered toward the document's tone
+// and aimed at the language the document is actually written in.
+func CheckpointMessages(contentText, tone string, t Target) []Message {
+	system := fmt.Sprintf(checkpointSystemPrompt, toneGuidance(tone))
+	if t.Flipped() {
+		system = fmt.Sprintf(pairCheckpointSystemPrompt, t.Correct.Name, t.Explain.Name, toneGuidance(tone))
+	}
 	return []Message{
-		{Role: "system", Content: fmt.Sprintf(checkpointSystemPrompt, toneGuidance(tone))},
+		{Role: "system", Content: system},
 		{Role: "user", Content: contentText},
 	}
 }
@@ -82,12 +126,48 @@ Respond ONLY with valid JSON. No preamble, no markdown fences. Format:
 
 If the voice is consistent throughout, return: {"suggestions": []}`
 
+// pairVoiceSystemPrompt is the voice pass for a document in the writer's own
+// language. Voice consistency is the one pass that transfers across languages
+// unchanged — a paragraph that reads as pasted from elsewhere reads that way in
+// any language — so only the framing and the explanation language move.
+const pairVoiceSystemPrompt = `You are a warm, encouraging writing assistant. The person you are helping is writing ` +
+	`in %[1]s. You are reviewing a COMPLETE %[1]s document for VOICE CONSISTENCY only — not grammar.
+
+Read the whole document to learn the writer's natural voice, then identify any passages (2 or more sentences) ` +
+	`that feel tonally inconsistent with the surrounding writing — unusually formal, unusually polished, or phrased ` +
+	`in a way that differs from the writer's established voice elsewhere in the document. These often signal text ` +
+	`that was paraphrased too closely from another source. Do not flag the first paragraph (there is no baseline yet). ` +
+	`Do not flag grammar or spelling mistakes — only voice.
+
+Quote each passage exactly as it appears, in %[1]s. Write every "explanation" in %[2]s.
+
+Respond ONLY with valid JSON. No preamble, no markdown fences. Format:
+{
+  "suggestions": [
+    {
+      "original": "exact passage from the document that feels inconsistent",
+      "replacement": null,
+      "explanation": "friendly one-sentence note about why this passage sounds unlike the rest",
+      "type": "voice"
+    }
+  ]
+}
+
+If the voice is consistent throughout, return: {"suggestions": []}`
+
 // VoiceMessages builds the message array for a voice-consistency pass. Unlike
 // the checkpoint, the caller passes the WHOLE document (no truncation) — voice
 // consistency is judged against the established voice everywhere else.
-func VoiceMessages(contentText string) []Message {
+//
+// The pass had no language argument at all before Phase 28, which was the same
+// English assumption the checkpoint made, just unstated.
+func VoiceMessages(contentText string, t Target) []Message {
+	system := voiceSystemPrompt
+	if t.Flipped() {
+		system = fmt.Sprintf(pairVoiceSystemPrompt, t.Correct.Name, t.Explain.Name)
+	}
 	return []Message{
-		{Role: "system", Content: voiceSystemPrompt},
+		{Role: "system", Content: system},
 		{Role: "user", Content: contentText},
 	}
 }
@@ -133,10 +213,17 @@ If every pairing already sounds natural, return: {"suggestions": []}`
 // CollocationMessages builds the message array for a collocation pass over the
 // WHOLE document (no truncation), gently steered toward the document's tone so a
 // hint can prefer a register-appropriate pairing. The parenthetical gloss is
-// written in the writer's own language.
-func CollocationMessages(contentText, tone string, lang Lang) []Message {
+// written in the writer's own language — `Pair`, not `Explain`: the gloss is
+// addressed to her rather than to the document.
+//
+// The coach itself remains English-only. Collocation lists are the one thing
+// here that is genuinely per-language knowledge rather than framing, and
+// "natives usually say" for Portuguese is a claim this prompt has no grounds to
+// make yet; a flipped document simply gets the pass it always got. (Phase 28
+// moved the checkpoint and the voice pass; this one waits for evidence.)
+func CollocationMessages(contentText, tone string, t Target) []Message {
 	return []Message{
-		{Role: "system", Content: fmt.Sprintf(collocationSystemPrompt, toneGuidance(tone), lang.Name)},
+		{Role: "system", Content: fmt.Sprintf(collocationSystemPrompt, toneGuidance(tone), t.Pair.Name)},
 		{Role: "user", Content: contentText},
 	}
 }
@@ -242,23 +329,29 @@ func RewriteMessages(text, style string) []Message {
 }
 
 // translateSystemPrompt drives the explanation translator: it renders a
-// suggestion's English explanation into the writer's own language so an ESL
-// reader sees the "why" in her first language. Strict about returning ONLY the
-// translation (no quotes, no romanisation, no English echo) so it can drop
-// straight into the chat bubble. Kept warm and plain — these are short, friendly
-// one-liners.
-const translateSystemPrompt = `You are Petal, a warm writing assistant. Translate the English text the user ` +
-	`sends into natural, friendly %[1]s. It is a short explanation of a writing ` +
-	`suggestion, written for a native %[1]s speaker learning English.
+// suggestion's explanation into the half of the pair the explanation is not
+// already in, so the "why" is readable from both sides. Strict about returning
+// ONLY the translation (no quotes, no romanisation, no echo of the source) so it
+// can drop straight into the chat bubble. Kept warm and plain — these are short,
+// friendly one-liners.
+//
+// Both languages are parameters because neither end is a constant. Until Phase
+// 28 the source was always English and the destination always hers; a document
+// written in her own language is explained in her own language, and then the tap
+// runs the other way, into the English she is practising.
+const translateSystemPrompt = `You are Petal, a warm writing assistant. Translate the %[1]s text the user ` +
+	`sends into natural, friendly %[2]s. It is a short explanation of a writing ` +
+	`suggestion, written for someone who is learning one of %[1]s and %[2]s and reads the other most easily.
 
-Respond with ONLY the %[1]s translation. No quotation marks, no romanisation, no English, no preamble — ` +
+Respond with ONLY the %[2]s translation. No quotation marks, no romanisation, no %[1]s, no preamble — ` +
 	`just the translated sentence.`
 
-// TranslateMessages builds the message array for translating one short English
-// explanation into the writer's own language.
-func TranslateMessages(text string, lang Lang) []Message {
+// TranslateMessages builds the message array for rendering one short
+// explanation out of the language it arrived in and into the other half of the
+// writer's pair.
+func TranslateMessages(text string, from, to Lang) []Message {
 	return []Message{
-		{Role: "system", Content: fmt.Sprintf(translateSystemPrompt, lang.Name)},
+		{Role: "system", Content: fmt.Sprintf(translateSystemPrompt, from.Name, to.Name)},
 		{Role: "user", Content: text},
 	}
 }

internal/llm/target.go

@@ -0,0 +1,54 @@
+package llm
+
+// Which language a pass corrects, and which language it explains in.
+//
+// Until Phase 28 there was no question to answer: every prompt was written
+// around English prose explained in English, and the pair language reached her
+// only when she asked for it (Ask Petal, the explanation translator). That is
+// the right default for a writer practising English and the wrong one for a
+// document she wrote in her own language, where Petal would read Portuguese,
+// say nothing about it, and file a mechanics note about the one English
+// sentence at the end.
+//
+// The two fields are two different decisions reading two different pieces of
+// state, and collapsing them would be the bug:
+//
+//   - Correct follows the DOCUMENT. Portuguese prose gets Portuguese
+//     corrections; that is the whole point.
+//   - Explain follows the WRITER — the half of her pair she is *not* learning
+//     (users.direction), because an explanation is teaching, and teaching lands
+//     in the language she reads most easily.
+//
+// Today those two coincide for every account that exists: `learnerPairs` is
+// {"zh"}, so fr, es and pt-PT writers are all `learning_en` and their
+// non-learned half *is* the pair language. That equality is a fact about
+// today's roster, not about the design — the same shape of assumption that had
+// to be unpicked from `pair_lang` in migration 0016. Keep them apart.
+type Target struct {
+	// Correct is the language the writing is in, and so the language both
+	// `original` and `replacement` must be written in.
+	Correct Lang
+	// Explain is the language each explanation is written in.
+	Explain Lang
+	// Pair is the writer's pair language regardless of what this document is
+	// written in. The collocation coach's parenthetical gloss is addressed to
+	// her rather than to the document, so it reads this and not Correct.
+	Pair Lang
+}
+
+// English as the prompts name it. Not in `langs`: that map answers "which
+// language is the writer's half of the pair", and English is the constant on
+// the other side of every pair Petal supports.
+var English = Lang{Code: "en", Name: "English", Why: "why"}
+
+// EnglishTarget is the pre-Phase-28 behaviour, made explicit: an English
+// document, corrected and explained in English, for a writer whose pair
+// language is `pair`. Every existing user is on this path and the prompt it
+// produces is byte-identical to the one that shipped before this phase.
+func EnglishTarget(pair Lang) Target {
+	return Target{Correct: English, Explain: English, Pair: pair}
+}
+
+// Flipped reports whether this document is in the pair language rather than in
+// English — i.e. whether the pass is reading her own language.
+func (t Target) Flipped() bool { return t.Correct.Code != English.Code }

internal/llm/target_test.go

@@ -0,0 +1,115 @@
+package llm
+
+import (
+	"strings"
+	"testing"
+)
+
+// The prompt every account is on today, written out in full.
+//
+// Phase 28 gave the checkpoint a second framing for documents in the writer's
+// own language, and the risk of that change is not that the new prompt is wrong
+// — it is that the old one moved by a word while nobody was looking. Every user
+// who exists is a Mandarin native writing English, so this string is the one
+// Petal actually sends, all day. It is duplicated here on purpose: a golden
+// copied from the constant it guards guards nothing.
+const goldenEnglishCheckpointPrompt = `You are a warm, encouraging writing assistant helping someone who speaks English as a second language. Analyze the text below and identify up to 5 issues: grammar errors, unnatural phrasing, incorrect idiom usage, or unclear sentences that are common ESL patterns.
+
+Be specific, friendly, and explain WHY each suggestion improves the writing.
+
+Respond ONLY with valid JSON. No preamble, no markdown fences. Format:
+{
+  "suggestions": [
+    {
+      "original": "exact text from the document that needs fixing",
+      "replacement": "corrected version",
+      "explanation": "friendly one-sentence explanation",
+      "type": "grammar|phrasing|idiom|clarity"
+    }
+  ]
+}
+
+If the writing looks good, return: {"suggestions": []}`
+
+func TestEnglishDocumentPromptIsUnchanged(t *testing.T) {
+	msgs := CheckpointMessages("I has two apple.", "", EnglishTarget(LangFor("zh")))
+	if got := msgs[0].Content; got != goldenEnglishCheckpointPrompt {
+		t.Fatalf("the English checkpoint prompt moved:\n--- got ---\n%s\n--- want ---\n%s", got, goldenEnglishCheckpointPrompt)
+	}
+	if msgs[1].Content != "I has two apple." {
+		t.Fatalf("document text mangled: %q", msgs[1].Content)
+	}
+
+	// The tone clause still lands, in the same place it always did.
+	toned := CheckpointMessages("x", "academic", EnglishTarget(LangFor("zh")))[0].Content
+	if !strings.Contains(toned, "formal, academic, and objective") {
+		t.Fatalf("English checkpoint lost its tone guidance:\n%s", toned)
+	}
+}
+
+// A document in her own language gets a prompt that names that language, keeps
+// the corrections inside it, and drops the framing that only makes sense when
+// the thing being written is English.
+func TestFlippedCheckpointPrompt(t *testing.T) {
+	pt := LangFor("pt-PT")
+	system := CheckpointMessages("Hoje foi um dia bom.", "casual", Target{Correct: pt, Explain: pt, Pair: pt})[0].Content
+
+	if !strings.Contains(system, "European Portuguese") {
+		t.Fatalf("flipped checkpoint doesn't name the language:\n%s", system)
+	}
+	if strings.Contains(system, "second language") || strings.Contains(system, "ESL") {
+		t.Fatalf("flipped checkpoint kept the ESL framing:\n%s", system)
+	}
+	if !strings.Contains(system, "never translate it into English") {
+		t.Fatalf("flipped checkpoint doesn't forbid translating:\n%s", system)
+	}
+	// The shared contract below the framing has to survive the split.
+	for _, want := range []string{`"suggestions"`, `"replacement"`, "grammar|phrasing|idiom|clarity", "relaxed, friendly, and conversational"} {
+		if !strings.Contains(system, want) {
+			t.Fatalf("flipped checkpoint dropped %q:\n%s", want, system)
+		}
+	}
+	if strings.Contains(system, "%!") {
+		t.Fatalf("flipped checkpoint has a formatting error:\n%s", system)
+	}
+}
+
+// The two decisions are separate arguments and must reach the prompt separately:
+// corrections in the document's language, the explanation in the language she
+// reads most easily. Only the zh pair can be travelled both ways today, so it is
+// the only one that can prove they haven't been quietly collapsed into one.
+func TestFlippedPromptsExplainInTheirOwnLanguage(t *testing.T) {
+	zh := LangFor("zh")
+
+	// Native Mandarin, practising English, writing Chinese: both halves Chinese.
+	both := CheckpointMessages("今天天气很好。", "", Target{Correct: zh, Explain: zh, Pair: zh})[0].Content
+	if strings.Count(both, "Simplified Chinese (Mandarin)") < 2 {
+		t.Fatalf("expected corrections and explanations both in Chinese:\n%s", both)
+	}
+	if strings.Contains(both, "explanation"+`" in English`) {
+		t.Fatalf("explanation language leaked to English:\n%s", both)
+	}
+
+	// Native English, learning Chinese, writing Chinese: Chinese corrections,
+	// English explanations.
+	split := CheckpointMessages("今天天气很好。", "", Target{Correct: zh, Explain: English, Pair: zh})[0].Content
+	if !strings.Contains(split, `Write every "explanation" in English.`) {
+		t.Fatalf("learner direction didn't get English explanations:\n%s", split)
+	}
+	if !strings.Contains(split, "writing in Simplified Chinese (Mandarin)") {
+		t.Fatalf("learner direction lost its Chinese corrections:\n%s", split)
+	}
+
+	// Same for the voice pass, which had no language at all before this phase.
+	voice := VoiceMessages("今天天气很好。", Target{Correct: zh, Explain: English, Pair: zh})[0].Content
+	if !strings.Contains(voice, `Write every "explanation" in English.`) || !strings.Contains(voice, "Simplified Chinese") {
+		t.Fatalf("flipped voice prompt got its languages wrong:\n%s", voice)
+	}
+	if strings.Contains(voice, "second language") {
+		t.Fatalf("flipped voice prompt kept the ESL framing:\n%s", voice)
+	}
+	// An English document still gets exactly the voice prompt it always got.
+	if got := VoiceMessages("x", EnglishTarget(zh))[0].Content; got != voiceSystemPrompt {
+		t.Fatalf("English voice prompt moved:\n%s", got)
+	}
+}

internal/llm/translate.go

@@ -4,13 +4,14 @@ import (
 	"context"
 )
 
-// RunTranslate renders a short English explanation into the writer's own
-// language. It is a one-shot Complete (the result seeds the Ask Petal bubble),
-// kept at a low temperature so the translation is faithful rather than creative. Output is
-// trimmed of any stray surrounding quotes the model may add.
-func RunTranslate(ctx context.Context, client LLMClient, text string, lang Lang) (string, error) {
+// RunTranslate renders a short explanation out of the language it was written
+// in and into the other half of the writer's pair. It is a one-shot Complete
+// (the result seeds the Ask Petal bubble), kept at a low temperature so the
+// translation is faithful rather than creative. Output is trimmed of any stray
+// surrounding quotes the model may add.
+func RunTranslate(ctx context.Context, client LLMClient, text string, from, to Lang) (string, error) {
 	out, err := client.Complete(ctx, CompletionRequest{
-		Messages:          TranslateMessages(text, lang),
+		Messages:          TranslateMessages(text, from, to),
 		MaxTokens:         512,
 		Temperature:       0.2,
 		TopP:              0.9,

internal/llm/voice.go

@@ -19,9 +19,9 @@ const VoiceInterval = 20 * time.Second
 // The tone argument is accepted for a uniform pass signature but ignored: voice
 // consistency is judged against the document's own established voice, not an
 // externally-chosen register.
-func RunVoice(ctx context.Context, client LLMClient, contentText, _ string, _ Lang) ([]RawSuggestion, error) {
+func RunVoice(ctx context.Context, client LLMClient, contentText, _ string, t Target) ([]RawSuggestion, error) {
 	raw, err := client.Complete(ctx, CompletionRequest{
-		Messages:          VoiceMessages(contentText),
+		Messages:          VoiceMessages(contentText, t),
 		MaxTokens:         2048,
 		Temperature:       0.3,
 		RepetitionPenalty: 1.15,

internal/suggestions/doclang.go

@@ -0,0 +1,179 @@
+package suggestions
+
+import "strings"
+
+// What language is this DOCUMENT in — as opposed to this span.
+//
+// `readsAsPairLang` next door answers a span-level question for the purpose of
+// labelling one card, and it is written to under-claim: two marker words, or
+// nothing. A whole document needs the opposite temperament. A proportion, not a
+// presence — one Portuguese quotation inside an English essay must not flip the
+// entire pass into Portuguese, and one English sentence at the end of a
+// Portuguese journal must not keep it in English.
+//
+// Three properties, in the order they bite:
+//
+//   - Decided over the WHOLE document, never a chunk. The grammar checkpoint
+//     sends only the sentences that changed, so a verdict computed from what it
+//     asked about would put an English card in a Portuguese journal the moment
+//     she edits its one English line. The caller passes content_text, always.
+//
+//   - Hysteresis. A bilingual paragraph sits near whatever single threshold we
+//     pick, and a document crossing it every few keystrokes would alternate card
+//     languages between passes — the same instability the mascot needed a band
+//     for. Flip to the pair at 70% and back only below 40%; in between, whatever
+//     it was last time stands. The band is the feature, not a rounding
+//     tolerance.
+//
+//   - Plain code, no model call. The house rule is that the LLM is garnish,
+//     never a gatekeeper: a document must not become uncheckable because the
+//     inference box is down.
+const (
+	docLangEnglish = "en"
+	docLangPair    = "pair"
+)
+
+// The band. Deliberately wide: the cost of an unnecessary flip is every card in
+// the document changing language, which is far more startling than a paragraph
+// of mixed writing being read as whichever language it was a minute ago.
+const (
+	flipToPairAt       = 0.70
+	flipToEnglishBelow = 0.40
+)
+
+// documentLang returns the language verdict for a document, given the verdict it
+// carried before. `prev` is "" for a document that has never been read.
+//
+// The result is one of docLangEnglish / docLangPair — not a language code. Which
+// language "pair" means is the writer's `pair_lang`, and keeping the stored
+// verdict relative to her pair means changing her pair doesn't strand a stale
+// language name on every document she owns.
+func documentLang(contentText, pairLang, prev string) string {
+	if prev != docLangPair {
+		prev = docLangEnglish
+	}
+	p := normalizePairLang(pairLang)
+	if !hasLangTest(p) {
+		// No test for this pair: say English, which is what every surface did
+		// before this phase. A wrong flip is louder than a missing one.
+		return docLangEnglish
+	}
+
+	var pair, english int
+	for _, c := range splitChunks(contentText, "") {
+		switch sentenceLang(c.text, p) {
+		case docLangPair:
+			pair++
+		case docLangEnglish:
+			english++
+		}
+	}
+	decided := pair + english
+	if decided == 0 {
+		// Nothing to go on — an empty document, a list of numbers, a title. Hold
+		// the previous verdict rather than resetting a Portuguese journal to
+		// English because she cleared it to start again.
+		return prev
+	}
+
+	ratio := float64(pair) / float64(decided)
+	switch {
+	case ratio >= flipToPairAt && corroborated(contentText, p):
+		return docLangPair
+	case ratio < flipToEnglishBelow:
+		return docLangEnglish
+	default:
+		return prev
+	}
+}
+
+// sentenceLang classifies one sentence as pair-language, English, or neither.
+//
+// Neither is a real answer and carries weight: a sentence with no evidence
+// either way ("Bom dia.", "OK.", a heading) is left out of the ratio entirely
+// rather than counted for the language it isn't. Counting the undecided as
+// English is what would keep a Portuguese document in English forever, since
+// short sentences carry no markers.
+func sentenceLang(s, p string) string {
+	if p == "zh" {
+		han, latin := scriptCounts(s)
+		switch {
+		case han >= 2 && han > latin:
+			return docLangPair
+		case latin >= 3 && latin > han:
+			return docLangEnglish
+		}
+		return ""
+	}
+	// A Latin pair shares its alphabet with English, so both sides are counted
+	// the same way and the larger pile of evidence wins. A tie — including no
+	// evidence at all — is no answer, which is why the English list below is
+	// curated as carefully against the pair languages as theirs is against
+	// English.
+	pair := distinctMarkers(s, latinMarkers[p])
+	eng := distinctMarkers(s, englishMarkers)
+	switch {
+	case pair > eng:
+		return docLangPair
+	case eng > pair:
+		return docLangEnglish
+	}
+	return ""
+}
+
+// corroborated requires the document as a whole to carry real evidence of the
+// pair language before the pass flips into it. A two-sentence document of
+// "Sim." / "Não." would otherwise reach 100% on almost nothing; a flip changes
+// every card in the document, so it has to be earned document-wide and not only
+// in proportion.
+func corroborated(contentText, p string) bool {
+	if p == "zh" {
+		han, _ := scriptCounts(contentText)
+		return han >= 8
+	}
+	return distinctMarkers(contentText, latinMarkers[p]) >= 3
+}
+
+// hasLangTest reports whether readsAsPairLang / sentenceLang know how to test
+// this pair at all. Kept beside the tests it describes so a new pair that adds
+// markers without adding itself here fails loudly in review rather than quietly
+// at runtime.
+func hasLangTest(p string) bool {
+	if p == "zh" {
+		return true
+	}
+	return len(latinMarkers[p]) > 0
+}
+
+// English function words, curated against the pair languages exactly as
+// `latinMarkers` is curated against English.
+//
+// Every word here is one a Portuguese, French or Spanish sentence has no reason
+// to contain. Deliberately absent, each a false English vote waiting to happen
+// in someone's own language: "on" and "son" (French), "as", "a", "o", "e", "no",
+// "os" (Portuguese), "no", "para", "sin" (Spanish), and "is"-alikes that are
+// really other languages' words. The list is short on purpose — it does not need
+// coverage, only a reliable vote in the sentences where the pair list is silent.
+var englishMarkers = words(
+	"the", "and", "is", "are", "was", "were", "be", "been", "being",
+	"of", "to", "that", "this", "these", "those", "with", "from", "for",
+	"have", "has", "had", "they", "them", "their", "there", "then", "than",
+	"what", "which", "when", "where", "why", "how", "who",
+	"will", "would", "should", "could", "can", "about", "because",
+	"into", "some", "such", "only", "very", "much", "many", "other",
+	"our", "your", "its", "it", "he", "she", "we", "you", "but", "not",
+	"just", "like", "also", "most", "over", "after", "before", "between",
+	"through", "said", "says", "get", "got", "make", "made", "know", "think",
+	"thing", "things", "time", "people", "here", "always", "never", "something",
+	"want", "need", "feel", "day", "today", "good", "really", "still", "even",
+)
+
+// normalizeDocLang folds a stored verdict into the two values the rest of the
+// code reasons about: the column holds "" for a document nothing has read yet,
+// and that means English, which is what every surface did before this phase.
+func normalizeDocLang(v string) string {
+	if strings.TrimSpace(v) == docLangPair {
+		return docLangPair
+	}
+	return docLangEnglish
+}

internal/suggestions/doclang_test.go

@@ -0,0 +1,536 @@
+package suggestions
+
+import (
+	"encoding/json"
+	"net/http"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+
+	"gitea.parodia.dev/drwily/petal/internal/auth"
+	"gitea.parodia.dev/drwily/petal/internal/db"
+	"gitea.parodia.dev/drwily/petal/internal/llm"
+)
+
+// A monolingual document in either language has to be read as that language, and
+// the mixed cases in between are where the whole design lives: one quotation
+// must not move a document, and one leftover English line must not hold a
+// journal in English.
+func TestDocumentLangReadsWholeDocuments(t *testing.T) {
+	const ptJournal = "Hoje foi um dia muito bom. Eu gosto de escrever aqui todas as noites. " +
+		"A minha irmã também quer aprender. Não sei porque isso é tão difícil para mim."
+	const enEssay = "The weather was very cold this morning. I think that the bus was late again. " +
+		"She told me about the meeting, but I could not hear what they said."
+	const zhJournal = "今天天气很好。我和妹妹一起去公园散步。我们看到很多花。"
+
+	tests := []struct {
+		name     string
+		text     string
+		pairLang string
+		prev     string
+		want     string
+	}{
+		{"portuguese journal", ptJournal, "pt-PT", "", docLangPair},
+		{"english essay", enEssay, "pt-PT", "", docLangEnglish},
+		{"chinese journal", zhJournal, "zh", "", docLangPair},
+		{"english essay, zh writer", enEssay, "zh", "", docLangEnglish},
+
+		// One English sentence at the end of a Portuguese journal is the case that
+		// motivated the whole phase: the pass must stay in Portuguese.
+		{
+			"portuguese with one english line",
+			ptJournal + " I will write more tomorrow.",
+			"pt-PT", "", docLangPair,
+		},
+		// And the mirror: an English essay quoting a line of Portuguese is still an
+		// English essay.
+		{
+			"english quoting portuguese",
+			enEssay + " She wrote: \"Eu não sei o que dizer.\"",
+			"pt-PT", "", docLangEnglish,
+		},
+		// A pair Petal has no test for cannot flip anything. Saying English is what
+		// every surface did before this phase.
+		{"untested pair", ptJournal, "de", "", docLangEnglish},
+		// Nothing to go on holds the previous answer rather than resetting a
+		// journal because she cleared it to start again.
+		{"emptied portuguese journal", "", "pt-PT", docLangPair, docLangPair},
+		{"emptied english essay", "   \n  ", "pt-PT", docLangEnglish, docLangEnglish},
+		// Proportion, not presence: a couple of Portuguese words are not a
+		// Portuguese document even though readsAsPairLang would label that span.
+		{
+			"english with a portuguese phrase",
+			enEssay + " The sign said pão com manteiga.",
+			"pt-PT", "", docLangEnglish,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := documentLang(tc.text, tc.pairLang, tc.prev); got != tc.want {
+				t.Fatalf("documentLang = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+// The band, from both directions. A document sitting inside it keeps whatever it
+// was, and that is the point: without it, a bilingual paragraph would alternate
+// its cards' language every few keystrokes as she typed across the threshold.
+func TestDocumentLangHysteresis(t *testing.T) {
+	// Half and half: two Portuguese sentences, two English ones. Inside the band
+	// from either side.
+	const mixed = "Eu gosto muito de escrever aqui. A minha irmã não sabe porque é difícil. " +
+		"The weather was very cold this morning. I think that they said the same thing."
+
+	if got := documentLang(mixed, "pt-PT", docLangEnglish); got != docLangEnglish {
+		t.Fatalf("mixed document from english = %q, want it to stay %q", got, docLangEnglish)
+	}
+	if got := documentLang(mixed, "pt-PT", docLangPair); got != docLangPair {
+		t.Fatalf("mixed document from pair = %q, want it to stay %q", got, docLangPair)
+	}
+
+	// Above the upper threshold it flips regardless of where it came from; below
+	// the lower one it flips back regardless.
+	const mostlyPT = "Eu gosto muito de escrever aqui. A minha irmã não sabe porque é difícil. " +
+		"Hoje foi um dia bom para mim. Amanhã também quero escrever mais uma coisa. " +
+		"I think so too."
+	if got := documentLang(mostlyPT, "pt-PT", docLangEnglish); got != docLangPair {
+		t.Fatalf("mostly-portuguese from english = %q, want %q", got, docLangPair)
+	}
+	const mostlyEN = "The weather was very cold this morning. I think that they said the same thing. " +
+		"She could not hear what the other people were saying about it. Eu não sei."
+	if got := documentLang(mostlyEN, "pt-PT", docLangPair); got != docLangEnglish {
+		t.Fatalf("mostly-english from pair = %q, want %q", got, docLangEnglish)
+	}
+}
+
+// Corroboration: a proportion computed over almost nothing is not evidence. Two
+// bare words at 100% must not flip a document, because a flip rewrites every
+// card in it.
+func TestDocumentLangNeedsCorroboration(t *testing.T) {
+	if got := documentLang("Não. Eu.", "pt-PT", docLangEnglish); got != docLangEnglish {
+		t.Fatalf("two bare words flipped the document: %q", got)
+	}
+	if got := documentLang("我。", "zh", docLangEnglish); got != docLangEnglish {
+		t.Fatalf("two Han runes flipped the document: %q", got)
+	}
+}
+
+// The Portuguese half of the same rule, and the bug it was reported as: "the
+// Portuguese option isn't translating the advice in English — it's just
+// reprinting Portuguese."
+//
+// Nothing was wrong with targetFor when that was reported. It was reading a
+// direction the account could not leave: `learnerPairs` held only zh, so every
+// pt-PT writer was learning_en by force and this function correctly explained a
+// Portuguese document in Portuguese. Pinned here rather than only in the auth
+// package because this is where the consequence actually lands — the language
+// the writer reads her advice in.
+func TestTargetExplainsPortugueseInEnglishForALearner(t *testing.T) {
+	learner := targetFor("pt-PT", auth.DirectionLearningPair, docLangPair)
+	if learner.Correct.Code != "pt-PT" {
+		t.Fatalf("corrected in %s, want the document's own Portuguese", learner.Correct.Code)
+	}
+	if learner.Explain.Code != "en" {
+		t.Fatalf("explained in %s, want English", learner.Explain.Code)
+	}
+
+	// And the native Portuguese speaker practising English is untouched: her
+	// Portuguese is still explained in Portuguese.
+	native := targetFor("pt-PT", auth.DirectionLearningEn, docLangPair)
+	if native.Correct.Code != "pt-PT" || native.Explain.Code != "pt-PT" {
+		t.Fatalf("learning_en on a Portuguese document: correct=%s explain=%s", native.Correct.Code, native.Explain.Code)
+	}
+}
+
+// The two language decisions are genuinely independent, and zh was the first
+// pair that could prove it — the first that could be travelled in both
+// directions.
+//
+// A Mandarin native practising English who writes Chinese wants Chinese
+// corrections explained in Chinese. An English native learning Chinese who writes
+// Chinese wants the same Chinese corrections explained in English. Same document,
+// same Correct, different Explain.
+func TestTargetSeparatesCorrectedFromExplained(t *testing.T) {
+	learningEn := targetFor("zh", auth.DirectionLearningEn, docLangPair)
+	if learningEn.Correct.Code != "zh" || learningEn.Explain.Code != "zh" {
+		t.Fatalf("learning_en on a Chinese document: correct=%s explain=%s", learningEn.Correct.Code, learningEn.Explain.Code)
+	}
+
+	learningPair := targetFor("zh", auth.DirectionLearningPair, docLangPair)
+	if learningPair.Correct.Code != "zh" {
+		t.Fatalf("learner direction changed what gets corrected: %s", learningPair.Correct.Code)
+	}
+	if learningPair.Explain.Code != "en" {
+		t.Fatalf("learner direction explained in %s, want English", learningPair.Explain.Code)
+	}
+
+	// An English document is the path every account is on today, in either
+	// direction: English corrections, English explanations, her language still on
+	// the Ask Petal and translate taps.
+	for _, dir := range []string{auth.DirectionLearningEn, auth.DirectionLearningPair} {
+		got := targetFor("zh", dir, docLangEnglish)
+		if got.Flipped() || got.Explain.Code != "en" {
+			t.Fatalf("english document with direction %s: %+v", dir, got)
+		}
+		if got.Pair.Code != "zh" {
+			t.Fatalf("english document lost the writer's pair: %+v", got)
+		}
+	}
+}
+
+// newDirectedServer seeds one writer on a given pair and direction, with a
+// document of her own. Like newPairServer, but the direction is the variable.
+func newDirectedServer(t *testing.T, client llm.LLMClient, pairLang, direction, text string) (http.Handler, string, *Handler) {
+	t.Helper()
+	database, err := db.Open(filepath.Join(t.TempDir(), "doclang.db"))
+	if err != nil {
+		t.Fatalf("open db: %v", err)
+	}
+	t.Cleanup(func() { database.Close() })
+
+	const userID = "writer-directed"
+	if _, err := database.Exec(
+		`INSERT INTO users (id, email, display_name, pair_lang, direction) VALUES (?, ?, ?, ?, ?)`,
+		userID, "d@example.com", "Writer", pairLang, direction,
+	); err != nil {
+		t.Fatalf("seed user: %v", err)
+	}
+
+	var docID string
+	if err := database.QueryRow(
+		`INSERT INTO documents (user_id, content_text) VALUES (?, ?) RETURNING id`,
+		userID, text,
+	).Scan(&docID); err != nil {
+		t.Fatalf("seed doc: %v", err)
+	}
+
+	h := New(database, client)
+	h.Limit = llm.NewRateLimiter(0)
+	h.VoiceLimit = llm.NewRateLimiter(0)
+	r := chi.NewRouter()
+	r.Route("/docs", func(dr chi.Router) { h.RegisterDocRoutes(dr) })
+	r.Mount("/suggestions", h.Routes())
+	return auth.Middleware(auth.StaticResolver(userID))(r), docID, h
+}
+
+const ptDocument = "Hoje foi um dia muito bom. Eu gosto de escrever aqui todas as noites. " +
+	"A minha irmã também quer aprender comigo. Não sei porque isso é tão difícil para mim."
+
+// End to end: a Portuguese document reaches the model as a Portuguese
+// checkpoint. This is the observed bug from 2026-07-28 — two pt-PT sentences
+// drew no cards at all, because Petal was reading them as bad English.
+func TestCheckpointFollowsTheDocumentLanguage(t *testing.T) {
+	client := &stubClient{response: `{"suggestions":[]}`}
+	srv, docID, _ := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, ptDocument)
+
+	if rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", ""); rec.Code != http.StatusOK {
+		t.Fatalf("check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if !strings.Contains(client.lastPrompt, "European Portuguese") {
+		t.Fatalf("checkpoint didn't follow the document into Portuguese:\n%s", client.lastPrompt)
+	}
+	if strings.Contains(client.lastPrompt, "second language") {
+		t.Fatalf("checkpoint kept the ESL framing on a Portuguese document:\n%s", client.lastPrompt)
+	}
+
+	// And the voice pass, which had no language argument at all before this phase.
+	if rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/voice", ""); rec.Code != http.StatusOK {
+		t.Fatalf("voice: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if !strings.Contains(client.lastPrompt, "European Portuguese") {
+		t.Fatalf("voice pass didn't follow the document:\n%s", client.lastPrompt)
+	}
+}
+
+// The verdict is persisted, because hysteresis needs a yesterday.
+func TestDocumentLangIsRemembered(t *testing.T) {
+	client := &stubClient{response: `{"suggestions":[]}`}
+	srv, docID, h := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, ptDocument)
+
+	if rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", ""); rec.Code != http.StatusOK {
+		t.Fatalf("check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	var stored string
+	if err := h.DB.QueryRow(`SELECT doc_lang FROM documents WHERE id = ?`, docID).Scan(&stored); err != nil {
+		t.Fatalf("read doc_lang: %v", err)
+	}
+	if stored != docLangPair {
+		t.Fatalf("doc_lang = %q, want %q", stored, docLangPair)
+	}
+}
+
+// A document that changes language re-opens every sentence. Without the verdict
+// in the chunk salt, the sentences she didn't touch would keep serving cards
+// written in the language the document no longer speaks.
+func TestLanguageFlipReopensCheckedSentences(t *testing.T) {
+	client := &stubClient{response: `{"suggestions":[]}`}
+	const enStart = "The weather was very cold this morning."
+	srv, docID, h := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, enStart)
+
+	if rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", ""); rec.Code != http.StatusOK {
+		t.Fatalf("first check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	first := client.calls
+
+	// She rewrites the document in Portuguese, keeping the first sentence.
+	setDocText(t, h, docID, enStart+" "+ptDocument)
+	if rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", ""); rec.Code != http.StatusOK {
+		t.Fatalf("second check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if client.calls == first {
+		t.Fatal("the flipped document was never sent to the model")
+	}
+	if !strings.Contains(client.lastPrompt, "The weather was very cold") {
+		t.Fatalf("the already-checked sentence was not re-opened by the flip:\n%s", client.lastPrompt)
+	}
+}
+
+// The translate card, pointed the other way. She is writing her journal in
+// Portuguese and drops in the one English sentence she knows; Petal renders it
+// into Portuguese, and that card is a translation — not a correction to prose
+// that was never wrong.
+func TestEnglishSpanBecomesATranslateCardInAPortugueseDocument(t *testing.T) {
+	const english = "I want to say this but I don't know how to say it."
+	// The model volunteers "clarity", as it did for the zh case. Not consulted.
+	client := &stubClient{response: `{"suggestions":[
+		{"original":"` + english + `","replacement":"Eu quero dizer isto mas não sei como o dizer.","explanation":"Aqui está em português.","type":"clarity"}
+	]}`}
+	srv, docID, _ := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, ptDocument+" "+english)
+
+	var out []db.Suggestion
+	rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if len(out) != 1 {
+		t.Fatalf("want 1 card, got %d: %+v", len(out), out)
+	}
+	if out[0].Type != db.SuggestionTypeTranslate {
+		t.Fatalf("card type = %q, want %q", out[0].Type, db.SuggestionTypeTranslate)
+	}
+}
+
+// And the half that keeps it honest: a genuine Portuguese correction in the same
+// document stays a correction. Reading the English-document test backwards would
+// have called this a translation, because every Portuguese sentence also "reads
+// as English" by that test's deliberately low bar.
+func TestPortugueseCorrectionKeepsItsTypeInAPortugueseDocument(t *testing.T) {
+	client := &stubClient{response: `{"suggestions":[
+		{"original":"Não sei porque isso é tão difícil para mim.","replacement":"Não sei porque isto é tão difícil para mim.","explanation":"Aqui usa-se isto.","type":"grammar"}
+	]}`}
+	srv, docID, _ := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, ptDocument)
+
+	var out []db.Suggestion
+	rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if len(out) != 1 {
+		t.Fatalf("want 1 card, got %d: %+v", len(out), out)
+	}
+	if out[0].Type == db.SuggestionTypeTranslate {
+		t.Fatal("a Portuguese correction inside a Portuguese document was labelled a translation")
+	}
+}
+
+// setDocLang writes a document's language verdict directly, so a test of the
+// tap-through doesn't have to run a checkpoint through the same stub client to
+// get one.
+func setDocLang(t *testing.T, h *Handler, docID, lang string) {
+	t.Helper()
+	if _, err := h.DB.Exec(`UPDATE documents SET doc_lang = ? WHERE id = ?`, lang, docID); err != nil {
+		t.Fatalf("set doc_lang: %v", err)
+	}
+}
+
+// seedExplanation files one card carrying a given explanation and returns its
+// id — the shape the translate tap-through needs, where only the explanation and
+// the document it hangs off matter.
+func seedExplanation(t *testing.T, h *Handler, docID, explanation string) string {
+	t.Helper()
+	var sugID string
+	if err := h.DB.QueryRow(
+		`INSERT INTO suggestions (doc_id, original, replacement, explanation, type, from_pos, to_pos)
+		 VALUES (?, ?, ?, ?, ?, 0, 5) RETURNING id`,
+		docID, "isso", "isto", explanation, "grammar",
+	).Scan(&sugID); err != nil {
+		t.Fatalf("seed suggestion: %v", err)
+	}
+	return sugID
+}
+
+// The tap-through has to read the same decision the card was written under. On a
+// Portuguese document by a Portuguese writer the explanation already arrived in
+// Portuguese, so the destination is the other half of the pair — the English she
+// is practising — and never Portuguese into Portuguese again.
+//
+// This pins the report that "Petal presents the Ask Petal advice in both
+// sections as Portuguese": the endpoint used to answer "" here, which left the
+// card Portuguese, the bubble beneath it the same Portuguese, and no English on
+// the card at all for a writer whose whole reason for the pair is English.
+func TestTranslateRendersHerExplanationIntoTheEnglishSheIsLearning(t *testing.T) {
+	client := &stubClient{response: "Use this one here."}
+	srv, docID, h := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, ptDocument)
+	setDocLang(t, h, docID, docLangPair)
+	sugID := seedExplanation(t, h, docID, "Aqui usa-se isto.")
+
+	rec := do(t, srv, http.MethodPost, "/suggestions/"+sugID+"/translate", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("translate: code=%d body=%s", rec.Code, rec.Body)
+	}
+	var out translateResponse
+	if err := json.Unmarshal(rec.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if out.Translation == "" {
+		t.Fatal("a Portuguese explanation left the tap with nowhere to go")
+	}
+	if !strings.Contains(client.lastPrompt, "into natural, friendly English") {
+		t.Fatalf("translate didn't render into English:\n%s", client.lastPrompt)
+	}
+	if strings.Contains(client.lastPrompt, "into natural, friendly European Portuguese") {
+		t.Fatalf("the model was asked to render Portuguese into Portuguese:\n%s", client.lastPrompt)
+	}
+}
+
+// The learner travelling the other way is the case that proves the endpoint
+// derives its destination rather than skipping whenever a document is flipped: a
+// native English speaker learning Chinese, writing Chinese, gets her
+// explanations in English — and the tap still has somewhere to go.
+func TestTranslateStillRendersForALearnersEnglishExplanation(t *testing.T) {
+	const zhDocument = "今天天气很好。我早上去公园散步。下午我在家里写作业。晚上我和朋友一起吃饭。"
+	client := &stubClient{response: "这里应该用这个。"}
+	srv, docID, h := newDirectedServer(t, client, "zh", auth.DirectionLearningPair, zhDocument)
+	setDocLang(t, h, docID, docLangPair)
+	sugID := seedExplanation(t, h, docID, "This measure word doesn't fit here.")
+
+	rec := do(t, srv, http.MethodPost, "/suggestions/"+sugID+"/translate", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("translate: code=%d body=%s", rec.Code, rec.Body)
+	}
+	var out translateResponse
+	if err := json.Unmarshal(rec.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if out.Translation == "" {
+		t.Fatal("a learner's English explanation was left untranslated")
+	}
+	if !strings.Contains(client.lastPrompt, "Simplified Chinese") {
+		t.Fatalf("translate didn't render into the pair language:\n%s", client.lastPrompt)
+	}
+}
+
+// TestPassAnnouncesItsVerdict pins the header the client reads. Storing the
+// verdict on the document row is not enough on its own: the editor sees that row
+// only when the document is opened or saved, and the pass that decides the
+// verdict runs *after* a save — so the client would always be one save behind,
+// and read-aloud is reached for exactly when she has stopped typing and no
+// further save is coming. Caught in a browser: a Portuguese paragraph read in an
+// American voice, twice, until another keystroke went in.
+//
+// Asserted on both endpoints that can flip it, and on the empty-document early
+// return, which answers without ever reaching the model.
+func TestPassAnnouncesItsVerdict(t *testing.T) {
+	client := &stubClient{response: `{"suggestions":[]}`}
+	srv, docID, h := newDirectedServer(t, client, "pt-PT", auth.DirectionLearningEn, ptDocument)
+
+	for _, path := range []string{"/check", "/voice"} {
+		rec := do(t, srv, http.MethodPost, "/docs/"+docID+path, "")
+		if rec.Code != http.StatusOK {
+			t.Fatalf("%s: code=%d body=%s", path, rec.Code, rec.Body)
+		}
+		if got := rec.Header().Get("X-Petal-Doc-Lang"); got != docLangPair {
+			t.Fatalf("%s: X-Petal-Doc-Lang = %q, want %q", path, got, docLangPair)
+		}
+	}
+
+	// An English document says so rather than saying nothing — the client has to
+	// be able to hear a flip back, not just a flip away.
+	if _, err := h.DB.Exec(
+		`UPDATE documents SET content_text = ?, doc_lang = '' WHERE id = ?`,
+		"The weather was very cold this morning. I walked to the shop and bought some bread.", docID,
+	); err != nil {
+		t.Fatalf("rewrite doc: %v", err)
+	}
+	rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/check", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if got := rec.Header().Get("X-Petal-Doc-Lang"); got != docLangEnglish {
+		t.Fatalf("English document: X-Petal-Doc-Lang = %q, want %q", got, docLangEnglish)
+	}
+
+	// The empty-document path returns before the model call, and still answers.
+	if _, err := h.DB.Exec(`UPDATE documents SET content_text = '' WHERE id = ?`, docID); err != nil {
+		t.Fatalf("empty doc: %v", err)
+	}
+	rec = do(t, srv, http.MethodPost, "/docs/"+docID+"/check", "")
+	if rec.Code != http.StatusOK {
+		t.Fatalf("empty check: code=%d body=%s", rec.Code, rec.Body)
+	}
+	if got := rec.Header().Get("X-Petal-Doc-Lang"); got == "" {
+		t.Fatal("empty document answered with no verdict header at all")
+	}
+}
+
+// TestOrdinaryProseIsEnoughEvidence is the regression for what the marker lists
+// were caught doing on 2026-07-29, live, in a browser: unremarkable Portuguese
+// read as English, because the list was curated against English so tightly that
+// it had also been curated against ordinary writing. The document below scored
+// two pair markers and zero English ones, and two is below the corroboration
+// floor — so a paragraph with no evidence of English in it at all came back
+// English, and was corrected and read aloud as English.
+//
+// Every sample here is prose a person might actually write, not prose chosen to
+// contain markers. That is the whole point of the test: the failure was invisible
+// to a suite whose fixtures all argued their own case.
+func TestOrdinaryProseIsEnoughEvidence(t *testing.T) {
+	samples := []struct{ name, text string }{
+		{"the one seen live", "Esta manhã acordei cedo e fui correr ao longo da marginal. O ar estava fresco e havia poucas pessoas na rua. Depois comprei um jornal e li-o sentado num banco ao sol."},
+		{"an afternoon out", "Hoje o céu estava limpo e fomos até ao jardim junto ao rio. A minha mãe trouxe uma manta velha e sentámos-nos debaixo de uma árvore."},
+		{"plans", "Amanhã vamos ao cinema depois do trabalho. Ontem estava demasiado cansada para sair de casa."},
+	}
+	for _, s := range samples {
+		if got := documentLang(s.text, "pt-PT", ""); got != docLangPair {
+			t.Errorf("%s: documentLang = %q, want %q — ordinary Portuguese must not read as English\n%s",
+				s.name, got, docLangPair, s.text)
+		}
+	}
+}
+
+// TestEnglishDidNotGetEasierToMistake is the other half, and the reason the
+// additions were held to "a word an English sentence has no reason to contain".
+// Widening a marker list is only safe if it widens in one direction: these are
+// English documents, including ones about Portugal and ones quoting Portuguese,
+// and every one of them must still come back English.
+func TestEnglishDidNotGetEasierToMistake(t *testing.T) {
+	samples := []struct{ name, text string }{
+		{"plain English", "This morning I woke up early and went for a run along the seafront. The air was fresh and there were few people about. Afterwards I bought a newspaper and read it on a bench."},
+		{"English about Portugal", "We spent a week in Lisbon last summer. The trams were crowded but the food was wonderful, and we walked up to the castle every evening."},
+		{"English quoting her", "My mother always says \"até amanhã\" when she leaves, never goodbye. I asked her why once and she said it sounded less final to her."},
+		{"an English diary", "Today was long. I had two meetings before lunch and another one after, and by the time I got home I could not think straight. Tomorrow should be quieter."},
+	}
+	for _, s := range samples {
+		if got := documentLang(s.text, "pt-PT", ""); got != docLangEnglish {
+			t.Errorf("%s: documentLang = %q, want %q — the widened list must not pull English across\n%s",
+				s.name, got, docLangEnglish, s.text)
+		}
+	}
+	// And the same document must not flip once it is already sitting in English:
+	// the hysteresis band is only a safety net if the low side holds too.
+	for _, s := range samples {
+		if got := documentLang(s.text, "pt-PT", docLangEnglish); got != docLangEnglish {
+			t.Errorf("%s: held verdict flipped to %q", s.name, got)
+		}
+	}
+}

internal/suggestions/handlers.go

@@ -247,12 +247,45 @@ func (h *Handler) collocation(w http.ResponseWriter, r *http.Request) {
 }
 
 // pass is the signature shared by the grammar checkpoint and the voice pass:
-// given the document text, the document's tone and the writer's pair language it
-// returns the model's raw suggestions. The voice pass ignores both extras (see
-// llm.RunVoice) and the checkpoint ignores the language — only the collocation
-// coach writes a word of it — but one signature keeps runPass free of special
-// cases.
-type pass func(ctx context.Context, client llm.LLMClient, contentText, tone string, lang llm.Lang) ([]llm.RawSuggestion, error)
+// given the document text, the document's tone and the languages this document
+// is to be corrected and explained in, it returns the model's raw suggestions.
+// The voice pass ignores the tone (see llm.RunVoice) and the collocation coach
+// reads only the writer's pair language, but one signature keeps runPass free of
+// special cases.
+type pass func(ctx context.Context, client llm.LLMClient, contentText, tone string, t llm.Target) ([]llm.RawSuggestion, error)
+
+// targetFor resolves the two language decisions for one pass over one document.
+//
+// They read different state on purpose. What gets *corrected* follows the
+// document, because Portuguese prose wants Portuguese corrections. What language
+// the correction is *explained* in follows the writer — the half of her pair she
+// is not learning — because an explanation is teaching, and teaching lands in the
+// language she reads most easily. A native Portuguese speaker practising English
+// gets Portuguese explained in Portuguese; a native English speaker learning
+// French gets French explained in English. Neither is trapped: the other language
+// stays one tap away, in both directions.
+//
+// An English document keeps the pre-Phase-28 behaviour exactly — explained in
+// English, with her language on the Ask Petal / translate taps — which is the
+// path every account today is on.
+//
+// The direction lookup costs nothing today: `learnerPairs` is {"zh"}, so fr, es
+// and pt-PT accounts are all learning_en and their non-learned half *is* the pair
+// language. This rule therefore produces "explain in the document's language" for
+// every writer who currently exists. It is written out anyway to stop the
+// coincidence being baked into the prompts, the way "English is the language
+// being learned" was baked into pair_lang before migration 0016.
+func targetFor(pairLang, direction, docLang string) llm.Target {
+	pair := llm.LangFor(pairLang)
+	if normalizeDocLang(docLang) != docLangPair {
+		return llm.EnglishTarget(pair)
+	}
+	explain := pair
+	if direction == auth.DirectionLearningPair {
+		explain = llm.English
+	}
+	return llm.Target{Correct: pair, Explain: explain, Pair: pair}
+}
 
 // runPass is the shared body for both LLM passes. It loads the document text,
 // enforces the pass's per-document rate limit, runs the model, swaps in the
@@ -262,17 +295,19 @@ func (h *Handler) runPass(w http.ResponseWriter, r *http.Request, limiter *llm.R
 	docID := chi.URLParam(r, "id")
 	userID := auth.UserID(r.Context())
 
-	// The writer's pair language rides along with the document rather than in a
-	// second query: it is read from the same row-scoped lookup that already
-	// proves she owns this document.
-	var contentText, tone, pairLang string
+	// The writer's pair language and direction ride along with the document
+	// rather than in a second query: they are read from the same row-scoped
+	// lookup that already proves she owns this document. `doc_lang` is the
+	// previous language verdict, which the new one needs (hysteresis).
+	var contentText, tone, pairLang, direction, prevLang string
 	err := h.DB.QueryRow(
-		`SELECT d.content_text, d.tone, COALESCE(u.pair_lang, '')
+		`SELECT d.content_text, d.tone, d.doc_lang,
+		        COALESCE(u.pair_lang, ''), COALESCE(u.direction, '')
 		   FROM documents d
 		   JOIN users u ON u.id = d.user_id
 		  WHERE d.id = ? AND d.user_id = ?`,
 		docID, userID,
-	).Scan(&contentText, &tone, &pairLang)
+	).Scan(&contentText, &tone, &prevLang, &pairLang, &direction)
 	if errors.Is(err, sql.ErrNoRows) {
 		httputil.ErrorJSON(w, http.StatusNotFound, "document not found")
 		return
@@ -282,10 +317,35 @@ func (h *Handler) runPass(w http.ResponseWriter, r *http.Request, limiter *llm.R
 		return
 	}
 
+	// What language is this document in, and so what language should its cards be
+	// written in? Computed from the whole content_text — never from `askText`,
+	// which on a chunked pass is only the sentences that changed, and would put an
+	// English card in a Portuguese journal the moment she edits its one English
+	// line.
+	//
+	// Decided before the empty-document exit so every reconcile below is told the
+	// same verdict. An emptied document has nothing to go on and holds whatever it
+	// said last (see documentLang), which is what keeps a Portuguese journal
+	// Portuguese while she clears it to start the entry again.
+	docLang := documentLang(contentText, pairLang, prevLang)
+
+	// Announce the verdict on every answer this pass gives, including the early
+	// ones below. This pass is the only thing that decides the value, so it is
+	// the only moment the client can learn it promptly — and the client needs it
+	// promptly for read-aloud, which is reached for exactly when she has stopped
+	// typing and no further save is coming. Carrying it back on the document row
+	// alone means the editor is always one save behind the truth, and a paragraph
+	// of Portuguese read in an American voice is how that sounds.
+	//
+	// A header rather than a wider body: /check and /voice answer with a bare
+	// array of the unified pending set, and every caller of both endpoints reads
+	// it as one. A verdict is metadata about the pass, not another suggestion.
+	w.Header().Set("X-Petal-Doc-Lang", docLang)
+
 	// Nothing to analyze on an empty document — skip the LLM round-trip. The
 	// family's rows go with the text they were about.
 	if strings.TrimSpace(contentText) == "" {
-		if err := h.reconcilePending(docID, contentText, pairLang, nil, scope, nil, nil, false); err != nil {
+		if err := h.reconcilePending(docID, contentText, pairLang, docLang, nil, scope, nil, nil, false); err != nil {
 			httputil.ServerError(w, err)
 			return
 		}
@@ -298,16 +358,30 @@ func (h *Handler) runPass(w http.ResponseWriter, r *http.Request, limiter *llm.R
 		return
 	}
 
+	if docLang != normalizeDocLang(prevLang) {
+		if _, err := h.DB.Exec(
+			`UPDATE documents SET doc_lang = ? WHERE id = ? AND user_id = ?`,
+			docLang, docID, userID,
+		); err != nil {
+			httputil.ServerError(w, err)
+			return
+		}
+	}
+	target := targetFor(pairLang, direction, docLang)
+
 	// Decide what to ask about before spending anything: a chunked pass asks only
 	// about the sentences that changed since it last read the document, and when
 	// none did it doesn't call the model at all — nor consume its rate-limit slot,
 	// so the next real edit isn't throttled by a check that had nothing to do.
 	//
 	// Only a chunked pass consults that record, so only it needs the tone folded
-	// into a sentence's identity.
+	// into a sentence's identity — and, next to it, the language verdict. A
+	// document that flips language changes every sentence's identity, so its
+	// old-language cards are re-checked rather than left sitting there in a
+	// language the rest of the document no longer speaks.
 	salt := ""
 	if scope.chunked {
-		salt = tone
+		salt = tone + "\x00" + docLang
 	}
 	chunks := splitChunks(contentText, salt)
 	askText, fresh := contentText, chunks
@@ -321,7 +395,7 @@ func (h *Handler) runPass(w http.ResponseWriter, r *http.Request, limiter *llm.R
 		if len(changed) == 0 {
 			// Every sentence has already been read. Drop the rows whose sentence is
 			// gone, keep the rest exactly as they are, and answer immediately.
-			if err := h.reconcilePending(docID, contentText, pairLang, nil, scope, chunks, nil, false); err != nil {
+			if err := h.reconcilePending(docID, contentText, pairLang, docLang, nil, scope, chunks, nil, false); err != nil {
 				httputil.ServerError(w, err)
 				return
 			}
@@ -354,7 +428,7 @@ func (h *Handler) runPass(w http.ResponseWriter, r *http.Request, limiter *llm.R
 		return
 	}
 
-	raw, err := run(r.Context(), h.Client, askText, tone, llm.LangFor(pairLang))
+	raw, err := run(r.Context(), h.Client, askText, tone, target)
 	if err != nil {
 		// Allow ran before the model call, so a failed pass would otherwise hold
 		// the per-document slot for the full interval — stranding the frontend's
@@ -366,7 +440,7 @@ func (h *Handler) runPass(w http.ResponseWriter, r *http.Request, limiter *llm.R
 
 	// A whole-document pass re-read everything, so every one of its rows is up for
 	// re-proposal; a chunked pass only puts the sentences it asked about in play.
-	if err := h.reconcilePending(docID, contentText, pairLang, raw, scope, chunks, fresh, !scope.chunked); err != nil {
+	if err := h.reconcilePending(docID, contentText, pairLang, docLang, raw, scope, chunks, fresh, !scope.chunked); err != nil {
 		httputil.ServerError(w, err)
 		return
 	}
@@ -764,13 +838,13 @@ func (h *Handler) setStatus(w http.ResponseWriter, r *http.Request, status strin
 // hands over a reusable chunk, which is the only thing worth reviewing in a week.
 func (h *Handler) plant(id, userID string) {
 	var s db.Suggestion
-	var contentText string
+	var contentText, docLang string
 	err := h.DB.QueryRow(
-		`SELECT s.type, s.original, s.replacement, s.explanation, s.doc_id, d.content_text
+		`SELECT s.type, s.original, s.replacement, s.explanation, s.doc_id, d.content_text, d.doc_lang
 		   FROM suggestions s JOIN documents d ON d.id = s.doc_id
 		  WHERE s.id = ? AND d.user_id = ?`,
 		id, userID,
-	).Scan(&s.Type, &s.Original, &s.Replacement, &s.Explanation, &s.DocID, &contentText)
+	).Scan(&s.Type, &s.Original, &s.Replacement, &s.Explanation, &s.DocID, &contentText, &docLang)
 	if err != nil {
 		if !errors.Is(err, sql.ErrNoRows) {
 			log.Printf("suggestions: could not read %s for planting: %v", id, err)
@@ -789,6 +863,9 @@ func (h *Handler) plant(id, userID string) {
 		Meaning: s.Explanation,
 		Example: correctedSentence(contentText, s.Original, s.Replacement),
 		DocID:   &docID,
+		// The chunk is her own sentence, corrected — so it is in the document's
+		// language, whatever the collocation pass was framed in.
+		Lang: docLang,
 	}); err != nil {
 		log.Printf("suggestions: could not plant %s: %v", id, err)
 	}

internal/suggestions/language.go

@@ -28,16 +28,35 @@ import (
 //     common words a sentence in that language can hardly avoid and an English
 //     sentence has no reason to contain.
 
-// isTranslation reports whether this edit is her own language rendered into
-// English, rather than a correction to her English. Both halves must hold: the
-// quoted span reads as the pair language, and what Petal offers back reads as
-// English. The second half matters — a Chinese span rewritten into different
-// Chinese is something else entirely, and Petal has no business calling it a
-// translation.
-func isTranslation(original, replacement, pairLang string) bool {
+// isTranslation reports whether this edit is a rendering of one language into
+// the other, rather than a correction. Both halves must hold: the quoted span
+// reads as one language, and what Petal offers back reads as the other. The
+// second half matters — a Chinese span rewritten into different Chinese is
+// something else entirely, and Petal has no business calling it a translation.
+//
+// Which way it points follows the document (Phase 28). In an English document
+// the translate card is her language rendered into English — she reached for a
+// sentence she couldn't say yet, and Petal said it for her. In a document she
+// wrote in her own language the useful card is the mirror image: an English
+// sentence she dropped into her Portuguese, rendered into Portuguese. Asking the
+// English-document question there would label nothing, and the card would file
+// as a correction to prose that was never wrong.
+//
+// The flipped direction cannot be the same test read backwards. `readsAsEnglish`
+// is a low bar on purpose — Latin letters, not swamped by another script — which
+// every Portuguese sentence also clears, so using it on the *original* would
+// call every genuine Portuguese correction a translation. The flipped test
+// instead uses the sentence-level vote from doclang.go, where English has its
+// own marker list and has to out-evidence the pair language to win.
+func isTranslation(original, replacement, pairLang, docLang string) bool {
 	if strings.TrimSpace(original) == "" || strings.TrimSpace(replacement) == "" {
 		return false
 	}
+	if normalizeDocLang(docLang) == docLangPair {
+		p := normalizePairLang(pairLang)
+		return sentenceLang(original, p) == docLangEnglish &&
+			sentenceLang(replacement, p) == docLangPair
+	}
 	return readsAsPairLang(original, pairLang) && readsAsEnglish(replacement)
 }
 
@@ -136,6 +155,19 @@ func distinctMarkers(s string, markers map[string]bool) int {
 //
 // A single marker is not enough (see readsAsPairLang), so these lists are read
 // as evidence to be corroborated rather than as a decision.
+//
+// **Curated against English is not the same as curated thinly**, and the first
+// version of these lists confused the two. Seen live 2026-07-29: "Esta manhã
+// acordei cedo e fui correr ao longo da marginal. O ar estava fresco e havia
+// poucas pessoas na rua." — unremarkable Portuguese, two marker hits, *zero*
+// English hits, and a verdict of English, because the document-level floor wants
+// three. The list was missing the ordinary machinery of the language: the
+// contractions (ao, à, num), the past tenses a diary is written in (estava,
+// havia, fomos), and the words that join two clauses (até, depois, então,
+// onde). Every one of them clears the bar above — an English sentence has no
+// reason to contain them — so their absence bought nothing and cost the verdict.
+// The floor stays at three; what changed is that three is now reachable by
+// prose rather than only by a paragraph that happens to argue with itself.
 var latinMarkers = map[string]map[string]bool{
 	"fr": words(
 		"je", "tu", "il", "elle", "ils", "elles", "nous", "vous", "est", "sont",
@@ -145,6 +177,10 @@ var latinMarkers = map[string]map[string]bool{
 		"beaucoup", "toujours", "jamais", "quand", "bien", "chose", "temps",
 		"moi", "toi", "lui", "peux", "veux", "sais", "faire", "dit", "aujourd",
 		"hui", "quelque", "chez", "tout", "tous", "rien", "déjà", "encore",
+		// The same gap the pt-PT list was caught with, closed by analogy rather
+		// than by observation — no fr account exists yet to catch it live.
+		"aux", "après", "où", "avait", "étaient", "depuis", "jusqu", "chaque",
+		"autre", "même", "hier", "demain", "matin", "soir", "nôtre", "leurs",
 	),
 	"pt-PT": words(
 		"eu", "você", "ele", "ela", "eles", "elas", "nós", "são", "uma", "os",
@@ -154,6 +190,18 @@ var latinMarkers = map[string]map[string]bool{
 		"nunca", "bem", "obrigado", "obrigada", "gosto", "tenho", "tem", "foi",
 		"ser", "ter", "mais", "já", "ainda", "aqui", "ali", "nada", "tudo",
 		"todos", "para", "pela", "pelo", "sobre", "assim",
+		// The contractions, which no English sentence has any use for.
+		"ao", "aos", "à", "às", "num", "numa", "dum", "duma", "pelos", "pelas",
+		"neste", "nesta", "disso", "deste", "desta",
+		// The tenses a journal is actually written in.
+		"estava", "estavam", "estão", "estamos", "havia", "houve", "era", "eram",
+		"fui", "fomos", "foram", "vai", "vamos", "tinha", "tinham",
+		// The joins between two clauses.
+		"até", "depois", "antes", "onde", "então", "enquanto", "embora",
+		"sem", "quem", "entre",
+		// And the everyday determiners and time words a diary can hardly avoid.
+		"nosso", "nossa", "outro", "outra", "mesmo", "mesma", "tão",
+		"muitos", "muitas", "poucos", "poucas", "hoje", "ontem", "amanhã",
 	),
 	"es": words(
 		"yo", "él", "ella", "ellos", "ellas", "nosotros", "una", "los", "las",
@@ -162,6 +210,12 @@ var latinMarkers = map[string]map[string]bool{
 		"hacer", "siempre", "nunca", "bien", "gracias", "tengo", "tiene", "fue",
 		"ser", "tener", "más", "aquí", "allí", "nada", "todos",
 		"para", "sobre", "así", "hola", "señor", "usted", "muchas",
+		// Likewise by analogy: no es account exists yet either. "sin" and "tan"
+		// stay out — both are English words, which is the one disqualification.
+		"al", "después", "antes", "donde", "entonces", "mientras", "aunque",
+		"estaba", "estaban", "están", "había", "hubo", "fuimos", "fueron",
+		"nuestro", "nuestra", "otro", "otra", "mismo", "misma", "quién", "quien",
+		"muchos", "pocas", "pocos", "hoy", "ayer", "mañana",
 	),
 }
 

internal/suggestions/language_test.go

@@ -3,6 +3,10 @@ package suggestions
 import "testing"
 
 // The flagship case, and the ones next to it that must NOT become translations.
+//
+// Every case here is an ENGLISH document — the path every account was on before
+// Phase 28 — so `docLang` is left at "". The mirror image lives in
+// TestIsTranslationInAPairLanguageDocument below.
 func TestIsTranslation(t *testing.T) {
 	cases := []struct {
 		name        string
@@ -134,8 +138,93 @@ func TestIsTranslation(t *testing.T) {
 
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
-			if got := isTranslation(c.original, c.replacement, c.pairLang); got != c.want {
-				t.Errorf("isTranslation(%q, %q, %q) = %v, want %v",
+			if got := isTranslation(c.original, c.replacement, c.pairLang, ""); got != c.want {
+				t.Errorf("isTranslation(%q, %q, %q, en) = %v, want %v",
+					c.original, c.replacement, c.pairLang, got, c.want)
+			}
+		})
+	}
+}
+
+// The mirror image (Phase 28): in a document she wrote in her own language, the
+// translate card is the English sentence rendered into her language — and the
+// English-document question, asked here, would label nothing.
+//
+// The case this file exists to pin is the third one: a genuine Portuguese
+// correction inside a Portuguese document. Reading the English-document test
+// backwards would call it a translation, because `readsAsEnglish` is a low bar
+// that Portuguese clears too. It has to stay a correction.
+func TestIsTranslationInAPairLanguageDocument(t *testing.T) {
+	cases := []struct {
+		name        string
+		original    string
+		replacement string
+		pairLang    string
+		want        bool
+	}{
+		{
+			name:        "English sentence rendered into Portuguese",
+			original:    "I want to say this but I don't know how to say it.",
+			replacement: "Eu quero dizer isso mas não sei como o dizer.",
+			pairLang:    "pt-PT",
+			want:        true,
+		},
+		{
+			name:        "English sentence rendered into Chinese",
+			original:    "I don't know how to say this in Chinese.",
+			replacement: "我不知道这句话用中文怎么说。",
+			pairLang:    "zh",
+			want:        true,
+		},
+		{
+			// The one that matters. Portuguese in, Portuguese out, inside a
+			// Portuguese document: a correction, and nothing else.
+			name:        "Portuguese corrected as Portuguese",
+			original:    "Eu quero dizer isso mas não sei como.",
+			replacement: "Eu quero dizer isto mas não sei como.",
+			pairLang:    "pt-PT",
+			want:        false,
+		},
+		{
+			// And its Chinese twin, which the script test already caught.
+			name:        "Chinese corrected as Chinese",
+			original:    "我想说这句话",
+			replacement: "我要说这句话",
+			pairLang:    "zh",
+			want:        false,
+		},
+		{
+			// The old direction, asked in the new document. She quoted English in
+			// her Portuguese and Petal rendered it into Portuguese — which IS a
+			// translation, and is the case above. This is its reverse: Portuguese
+			// out of an English document that isn't one. No label.
+			name:        "Portuguese rendered into English is not this document's translation",
+			original:    "Eu quero dizer isso mas não sei como.",
+			replacement: "I want to say this but I don't know how.",
+			pairLang:    "pt-PT",
+			want:        false,
+		},
+		{
+			// English prose without enough evidence to vote. Silence, not a guess.
+			name:        "too short to read as English",
+			original:    "OK",
+			replacement: "Está bem, muito obrigado.",
+			pairLang:    "pt-PT",
+			want:        false,
+		},
+		{
+			name:        "unknown pair language declines in both directions",
+			original:    "I don't know how to say that.",
+			replacement: "Ich weiß nicht wie man das sagt.",
+			pairLang:    "de",
+			want:        false,
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if got := isTranslation(c.original, c.replacement, c.pairLang, docLangPair); got != c.want {
+				t.Errorf("isTranslation(%q, %q, %q, pair) = %v, want %v",
 					c.original, c.replacement, c.pairLang, got, c.want)
 			}
 		})

internal/suggestions/plant_test.go

@@ -184,3 +184,60 @@ func TestCorrectedSentence(t *testing.T) {
 		t.Errorf("unterminated doc: got %q", got)
 	}
 }
+
+// TestPlantedPhraseCarriesTheDocumentLanguage: a chunk planted out of a document
+// written in her own language is a card in that language. The collocation pass
+// itself deliberately did not flip in Phase 28 — its prompt is per-language
+// knowledge, not framing — but the phrase it hands over is still lifted from her
+// prose, so the card has to know what language that prose was in or the garden
+// will read it aloud in the wrong voice.
+func TestPlantedPhraseCarriesTheDocumentLanguage(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	if _, err := h.DB.Exec(`UPDATE documents SET doc_lang = 'pair' WHERE id = ?`, docID); err != nil {
+		t.Fatalf("set doc_lang: %v", err)
+	}
+	id := seedSuggestion(t, h, docID,
+		"Ontem foi difícil. Tive de tomar uma decisão sobre o trabalho.",
+		db.SuggestionTypeCollocation, "tomar uma decisão", "tomar uma decisão",
+		"Em português diz-se “tomar” uma decisão.")
+
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept: got %d, want 204", rec.Code)
+	}
+
+	var lang string
+	if err := h.DB.QueryRow(
+		`SELECT lang FROM vocab_words WHERE user_id = ? AND word = ?`,
+		db.LocalUserID, "tomar uma decisão",
+	).Scan(&lang); err != nil {
+		t.Fatalf("read planted card: %v", err)
+	}
+	if lang != "pair" {
+		t.Fatalf("planted card lang = %q, want pair", lang)
+	}
+}
+
+// TestPlantedPhraseOnAnEnglishDocumentIsUnchanged is the other half, and the one
+// every account is on today: an English document plants an English card, and the
+// empty backfill and 'en' both mean that.
+func TestPlantedPhraseOnAnEnglishDocumentIsUnchanged(t *testing.T) {
+	srv, docID, h := newTestServer(t, &stubClient{})
+	id := seedSuggestion(t, h, docID, "I had to do a decision about the job.",
+		db.SuggestionTypeCollocation, "do a decision", "make a decision",
+		"English pairs “make” with “decision”.")
+
+	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
+		t.Fatalf("accept: got %d, want 204", rec.Code)
+	}
+
+	var lang string
+	if err := h.DB.QueryRow(
+		`SELECT lang FROM vocab_words WHERE user_id = ? AND word = ?`,
+		db.LocalUserID, "make a decision",
+	).Scan(&lang); err != nil {
+		t.Fatalf("read planted card: %v", err)
+	}
+	if lang == "pair" {
+		t.Fatalf("planted card lang = %q on an English document, want en or empty", lang)
+	}
+}

internal/suggestions/reconcile.go

@@ -131,10 +131,12 @@ func reposition(tx *sql.Tx, row pendingRow, from, to int, chunkHash string) erro
 // collocation coach — where every row is up for re-proposal because the model
 // just re-read everything.
 //
-// `pairLang` is the writer's own language, needed only to type a finding that
-// turns out to be her language rendered into English (see language.go).
+// `pairLang` is the writer's own language and `docLang` this document's language
+// verdict; between them they type a finding that turns out to be one language
+// rendered into the other, in whichever direction this document makes useful
+// (see language.go).
 func (h *Handler) reconcilePending(
-	docID, contentText, pairLang string,
+	docID, contentText, pairLang, docLang string,
 	raw []llm.RawSuggestion,
 	scope pendingScope,
 	chunks, fresh []chunk,
@@ -235,7 +237,7 @@ func (h *Handler) reconcilePending(
 		typ := scope.forceType
 		if typ == "" {
 			typ = normalizeType(s.Type)
-			if isTranslation(s.Original, s.Replacement, pairLang) {
+			if isTranslation(s.Original, s.Replacement, pairLang, docLang) {
 				typ = db.SuggestionTypeTranslate
 			}
 		}

internal/suggestions/translate.go

@@ -17,23 +17,44 @@ type translateResponse struct {
 	Translation string `json:"translation"`
 }
 
-// translate renders a suggestion's English explanation into Simplified Chinese
-// for the Ask Petal bubble, so the ESL reader sees the "why" in her first
-// language instead of a second copy of the same English text. The explanation is
-// loaded server-side from the suggestion id (scoped to the local user) and never
-// trusted from the client, mirroring chat (spec Note #10).
+// translate renders a suggestion's explanation into the other half of the
+// writer's pair for the Ask Petal bubble, so she sees the "why" in the language
+// she reads most easily instead of a second copy of the same text. The
+// explanation is loaded server-side from the suggestion id (scoped to the
+// caller) and never trusted from the client, mirroring chat (spec Note #10).
+//
+// Which language it renders into cannot be assumed (Phase 28). Before that phase
+// every explanation was English and every rendering went into her language, so
+// "the pair language" was a safe constant. Now the explanation's language is a
+// decision — `targetFor`, from the document's verdict and her direction — and
+// this endpoint has to read the same decision back, or it round-trips Portuguese
+// into Portuguese and calls it a translation.
+//
+// So: render into whichever half the explanation is NOT already in — and that
+// is the whole rule, in both directions. When it first shipped this endpoint
+// answered "" for a Portuguese explanation on the reasoning that an English
+// rendering she hadn't asked for was noise. It was reported as the opposite: a
+// writer whose pair is Portuguese and English, learning English, met a
+// Portuguese card with a Portuguese bubble under it and no English anywhere on
+// the card. The tap is the one place the other language was promised, and the
+// half she is *practising* is exactly the half worth a tap.
+//
+// The bubble sits directly beneath the explanation inside the card, so between
+// the two the writer always has both languages, whichever way round the document
+// put them.
 func (h *Handler) translate(w http.ResponseWriter, r *http.Request) {
 	sugID := chi.URLParam(r, "id")
 
-	var explanation, pairLang string
+	var explanation, pairLang, direction, docLang string
 	err := h.DB.QueryRow(
-		`SELECT s.explanation, COALESCE(u.pair_lang, '')
+		`SELECT s.explanation, COALESCE(u.pair_lang, ''),
+		        COALESCE(u.direction, ''), d.doc_lang
 		   FROM suggestions s
 		   JOIN documents d ON d.id = s.doc_id
 		   JOIN users u ON u.id = d.user_id
 		  WHERE s.id = ? AND d.user_id = ?`,
 		sugID, auth.UserID(r.Context()),
-	).Scan(&explanation, &pairLang)
+	).Scan(&explanation, &pairLang, &direction, &docLang)
 	if errors.Is(err, sql.ErrNoRows) {
 		httputil.ErrorJSON(w, http.StatusNotFound, "suggestion not found")
 		return
@@ -49,7 +70,20 @@ func (h *Handler) translate(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	out, err := llm.RunTranslate(r.Context(), h.Client, explanation, llm.LangFor(pairLang))
+	// The explanation's own language, recovered from the same rule that chose it
+	// when the card was written. A card written before this phase — or on a
+	// document whose verdict has since flipped — is read as whatever the rule says
+	// today; the alternative is a language column on every suggestion row, and the
+	// cost of being wrong is one bubble seeded in the language it was already in.
+	target := targetFor(pairLang, direction, docLang)
+	from, to := target.Explain, target.Pair
+	if from.Code == to.Code {
+		// The explanation is already in her language, so the half this tap has to
+		// reach is the other one: the English she is practising.
+		to = llm.English
+	}
+
+	out, err := llm.RunTranslate(r.Context(), h.Client, explanation, from, to)
 	if err != nil {
 		httputil.UpstreamError(w, "translate", err)
 		return

internal/vocab/handlers.go

@@ -26,6 +26,11 @@ type Word struct {
 	Phonetic   string  `json:"phonetic"`
 	Example    string  `json:"example"`
 	DocID      *string `json:"doc_id"`
+	// Lang is '' | 'en' | 'pair' — the language of the document the word was met
+	// in (see migration 0018). '' reads as English, like everywhere else this
+	// vocabulary appears. The client needs it to pick a read-aloud voice: "comum"
+	// is unguessable from its letters, so the card has to carry the answer.
+	Lang         string     `json:"lang"`
 	DueAt        time.Time  `json:"due_at"`
 	IntervalDays int        `json:"interval_days"`
 	Ease         float64    `json:"ease"`
@@ -54,7 +59,7 @@ func (h *Handler) Routes() chi.Router {
 	return r
 }
 
-const vocabColumns = `id, word, gloss, definition, phonetic, example, doc_id,
+const vocabColumns = `id, word, gloss, definition, phonetic, example, doc_id, lang,
 	due_at, interval_days, ease, reps, lapses, last_reviewed, created_at`
 
 func scanWord(s interface {
@@ -62,7 +67,7 @@ func scanWord(s interface {
 }) (Word, error) {
 	var w Word
 	err := s.Scan(
-		&w.ID, &w.Word, &w.Gloss, &w.Definition, &w.Phonetic, &w.Example, &w.DocID,
+		&w.ID, &w.Word, &w.Gloss, &w.Definition, &w.Phonetic, &w.Example, &w.DocID, &w.Lang,
 		&w.DueAt, &w.IntervalDays, &w.Ease, &w.Reps, &w.Lapses, &w.LastReviewed, &w.CreatedAt,
 	)
 	return w, err
@@ -165,15 +170,22 @@ func (h *Handler) capture(w http.ResponseWriter, r *http.Request) {
 	// would hit the foreign key and leak a raw "FOREIGN KEY constraint" 500
 	// instead of a clean 400 (and, once auth lands, would let a word be attached
 	// to another user's document).
+	//
+	// The same row-scoped lookup answers what language the card is in: a word is
+	// met inside a document, so the document's verdict is the word's language.
+	// Asking the document rather than trusting a `lang` in the request body is
+	// the same choice `runPass` makes — the client never gets to name a language
+	// the server can already read. A word with no document is '', which reads as
+	// English.
+	lang := ""
 	if req.DocID != nil {
 		if strings.TrimSpace(*req.DocID) == "" {
 			req.DocID = nil
 		} else {
-			var ok int
 			err := h.DB.QueryRow(
-				`SELECT 1 FROM documents WHERE id = ? AND user_id = ?`,
+				`SELECT doc_lang FROM documents WHERE id = ? AND user_id = ?`,
 				*req.DocID, userID,
-			).Scan(&ok)
+			).Scan(&lang)
 			if errors.Is(err, sql.ErrNoRows) {
 				httputil.ErrorJSON(w, http.StatusBadRequest, "unknown doc_id")
 				return
@@ -189,15 +201,19 @@ func (h *Handler) capture(w http.ResponseWriter, r *http.Request) {
 	// schedule (due_at/reps/interval/ease) alone so re-looking-up a word never
 	// resets its progress.
 	_, err := h.DB.Exec(
-		`INSERT INTO vocab_words (user_id, word, gloss, definition, phonetic, example, doc_id, due_at, interval_days)
-		 VALUES (?, ?, ?, ?, ?, ?, ?, datetime('now', '+1 day'), 1)
+		`INSERT INTO vocab_words (user_id, word, gloss, definition, phonetic, example, doc_id, lang, due_at, interval_days)
+		 VALUES (?, ?, ?, ?, ?, ?, ?, ?, datetime('now', '+1 day'), 1)
 		 ON CONFLICT(user_id, word) DO UPDATE SET
 		   gloss      = excluded.gloss,
 		   definition = excluded.definition,
 		   phonetic   = excluded.phonetic,
 		   example    = CASE WHEN excluded.example != '' THEN excluded.example ELSE vocab_words.example END,
-		   doc_id     = COALESCE(excluded.doc_id, vocab_words.doc_id)`,
-		userID, word, req.Gloss, req.Definition, req.Phonetic, req.Example, req.DocID,
+		   doc_id     = COALESCE(excluded.doc_id, vocab_words.doc_id),
+		   -- lang travels with doc_id, and for the same reason: it is the new
+		   -- context or it is nothing. A lookup made outside any document must
+		   -- not relabel a card that was captured inside one.
+		   lang       = CASE WHEN excluded.doc_id IS NOT NULL THEN excluded.lang ELSE vocab_words.lang END`,
+		userID, word, req.Gloss, req.Definition, req.Phonetic, req.Example, req.DocID, lang,
 	)
 	if err != nil {
 		httputil.ServerError(w, err)

internal/vocab/handlers_test.go

@@ -253,3 +253,89 @@ func TestDocLinkSurvivesDocDelete(t *testing.T) {
 		t.Fatalf("doc_id should be nulled after doc delete, got %v", *all[0].DocID)
 	}
 }
+
+// TestCaptureTakesLanguageFromItsDocument is the garden's half of Phase 28: a
+// word met inside a document written in her own language is a card in that
+// language, and the server reads that off the document rather than being told.
+//
+// The three cases are the three the client can actually produce: a lookup inside
+// a flipped document, a lookup inside an English one, and a lookup with no
+// document at all (the search box) — the last of which is '', which reads as
+// English everywhere this value is used.
+func TestCaptureTakesLanguageFromItsDocument(t *testing.T) {
+	srv, database := newTestServer(t)
+
+	seed := func(lang string) string {
+		t.Helper()
+		var id string
+		if err := database.QueryRow(
+			`INSERT INTO documents (user_id, content_text, doc_lang) VALUES (?, 'hi', ?) RETURNING id`,
+			db.LocalUserID, lang,
+		).Scan(&id); err != nil {
+			t.Fatalf("seed doc: %v", err)
+		}
+		return id
+	}
+	pairDoc, enDoc := seed("pair"), seed("en")
+
+	capture := func(word, body string) Word {
+		t.Helper()
+		rec := do(t, srv, http.MethodPost, "/vocab", body)
+		if rec.Code != http.StatusCreated {
+			t.Fatalf("capture %s: code=%d body=%s", word, rec.Code, rec.Body)
+		}
+		var w Word
+		if err := json.Unmarshal(rec.Body.Bytes(), &w); err != nil {
+			t.Fatalf("decode %s: %v", word, err)
+		}
+		return w
+	}
+
+	if got := capture("comum", `{"word":"comum","doc_id":"`+pairDoc+`"}`); got.Lang != "pair" {
+		t.Fatalf("word from a flipped document: lang=%q, want pair", got.Lang)
+	}
+	if got := capture("reception", `{"word":"reception","doc_id":"`+enDoc+`"}`); got.Lang != "en" {
+		t.Fatalf("word from an English document: lang=%q, want en", got.Lang)
+	}
+	if got := capture("orphan", `{"word":"orphan"}`); got.Lang != "" {
+		t.Fatalf("word with no document: lang=%q, want empty", got.Lang)
+	}
+
+	// A client that names a language is ignored: the document is the authority,
+	// the same way runPass never lets the request pick its own target.
+	if got := capture("comum", `{"word":"comum","lang":"en","doc_id":"`+pairDoc+`"}`); got.Lang != "pair" {
+		t.Fatalf("client-supplied lang should not win: lang=%q, want pair", got.Lang)
+	}
+}
+
+// TestRecaptureOutsideADocumentKeepsItsLanguage pins the one asymmetry in the
+// upsert. Re-looking-up a word refreshes its context, but a lookup made with no
+// document carries no verdict — and relabelling a Portuguese card English
+// because she checked the word again from the search box would silently move it
+// to the wrong voice. lang travels with doc_id, or it doesn't travel.
+func TestRecaptureOutsideADocumentKeepsItsLanguage(t *testing.T) {
+	srv, database := newTestServer(t)
+	var docID string
+	if err := database.QueryRow(
+		`INSERT INTO documents (user_id, content_text, doc_lang) VALUES (?, 'olá', 'pair') RETURNING id`,
+		db.LocalUserID,
+	).Scan(&docID); err != nil {
+		t.Fatalf("seed doc: %v", err)
+	}
+	if rec := do(t, srv, http.MethodPost, "/vocab",
+		`{"word":"saudade","gloss":"","doc_id":"`+docID+`"}`); rec.Code != http.StatusCreated {
+		t.Fatalf("capture: code=%d body=%s", rec.Code, rec.Body)
+	}
+	rec := do(t, srv, http.MethodPost, "/vocab", `{"word":"saudade","gloss":"longing"}`)
+	if rec.Code != http.StatusCreated {
+		t.Fatalf("recapture: code=%d body=%s", rec.Code, rec.Body)
+	}
+	var w Word
+	_ = json.Unmarshal(rec.Body.Bytes(), &w)
+	if w.Lang != "pair" {
+		t.Fatalf("recapture outside a document: lang=%q, want pair held", w.Lang)
+	}
+	if w.Gloss != "longing" {
+		t.Fatalf("recapture should still refresh the gloss, got %q", w.Gloss)
+	}
+}

internal/vocab/plant.go

@@ -28,6 +28,10 @@ type Phrase struct {
 	Meaning string  // why it's better — the suggestion's explanation
 	Example string  // the sentence she met it in, already corrected
 	DocID   *string // where, so "where did I see this?" stays one tap
+	// Lang is the document's verdict ('' | 'en' | 'pair'), because the chunk is
+	// lifted out of her own prose and is therefore in whatever language that
+	// prose is. See migration 0018.
+	Lang string
 }
 
 // Phrase-card caps. A collocation is a short chunk; anything longer is a
@@ -84,13 +88,14 @@ func Plant(ex Execer, userID string, p Phrase) (bool, error) {
 		return false, nil
 	}
 	res, err := ex.Exec(
-		`INSERT INTO vocab_words (user_id, word, gloss, definition, phonetic, example, doc_id, due_at, interval_days)
-		 VALUES (?, ?, '', ?, '', ?, ?, datetime('now', '+1 day'), 1)
+		`INSERT INTO vocab_words (user_id, word, gloss, definition, phonetic, example, doc_id, lang, due_at, interval_days)
+		 VALUES (?, ?, '', ?, '', ?, ?, ?, datetime('now', '+1 day'), 1)
 		 ON CONFLICT(user_id, word) DO NOTHING`,
 		userID, key,
 		clamp(strings.TrimSpace(p.Meaning), maxDefinitionLen),
 		clamp(strings.TrimSpace(p.Example), maxExampleLen),
 		p.DocID,
+		p.Lang,
 	)
 	if err != nil {
 		return false, err

web/src/App.tsx

@@ -1,5 +1,14 @@
 import { useCallback, useEffect, useRef, useState } from 'react'
-import { api, type DocSummary, type DocUpdate, type Document, type Suggestion, type Tag, type TagColor } from './api/client'
+import {
+  api,
+  onDocLang,
+  type DocSummary,
+  type DocUpdate,
+  type Document,
+  type Suggestion,
+  type Tag,
+  type TagColor,
+} from './api/client'
 import { useAutoSave } from './hooks/useAutoSave'
 import { findingKey, useCheckpoint } from './hooks/useCheckpoint'
 import { useSpellChecker } from './hooks/useSpellChecker'
@@ -81,13 +90,41 @@ export default function App() {
     return wordCountRef.current === 0 && (t === '' || t === 'Untitled')
   }, [])
 
-  const { status, schedule, saveNow } = useAutoSave(currentDoc?.id ?? null)
+  // The pass announces its verdict the moment it decides one, which is the only
+  // moment that is prompt enough: read-aloud is reached for when she has stopped
+  // typing, so waiting for the next save means waiting for a save that isn't
+  // coming. Registered once, and it updates the same one field the save path
+  // does — whichever arrives first wins, and they agree.
+  useEffect(() => {
+    onDocLang((docId, lang) =>
+      setCurrentDoc((prev) => (prev && prev.id === docId && prev.doc_lang !== lang ? { ...prev, doc_lang: lang } : prev)),
+    )
+  }, [])
+
+  // Only `doc_lang` is lifted out of the save response, and only when it moved.
+  // It is the one field the server decides on its own — the checkpoint pass reads
+  // the whole document and writes back whether it is English or hers — so it is
+  // the one field that would otherwise go stale under her while she writes. Read
+  // -aloud is what notices: a Portuguese paragraph read in an American voice.
+  // Everything else in the response is what the client just sent, and copying it
+  // back mid-keystroke would be a way to lose a character, not to gain one.
+  const { status, schedule, saveNow } = useAutoSave(currentDoc?.id ?? null, (saved) =>
+    setCurrentDoc((prev) =>
+      prev && prev.id === saved.id && prev.doc_lang !== saved.doc_lang ? { ...prev, doc_lang: saved.doc_lang } : prev,
+    ),
+  )
   // The Chinese word list, for a writer going the other way through the zh pair.
   // Gated on the account's own setting rather than on anything in the text: a
   // Mandarin native drafting English quotes Chinese constantly, and none of that
   // is what segmentation is for. Declared above the checkpoint because the
   // offline 错别字 pass reads it.
-  const segmenter = useSegmenter(me?.direction === 'learning_pair')
+  //
+  // Both halves of the gate matter now that Chinese is not the only pair with a
+  // learner direction. `learning_pair` alone used to imply zh; a writer learning
+  // Portuguese is also learning_pair and has no use for a megabyte of Chinese
+  // word list — nor for the hanzi hover it turns on, which would ask /api/hanzi
+  // about Portuguese words.
+  const segmenter = useSegmenter(me?.direction === 'learning_pair' && me?.pair_lang === 'zh')
 
   const {
     suggestions,
@@ -615,6 +652,7 @@ export default function App() {
                   <EditorCore
                     key={`${currentDoc.id}:${editorEpoch}`}
                     docId={currentDoc.id}
+                    docLang={currentDoc.doc_lang}
                     initialContent={currentDoc.content}
                     onChange={handleEditorChange}
                     segmenter={segmenter}

web/src/api/client.ts

@@ -44,8 +44,18 @@ export interface Document {
   // When true, this document's automatic snapshots are never pruned, so its
   // full writing trail survives as authorship evidence (see the passport).
   preserve_history: boolean
+  // Which language this document is written in, as decided server-side by the
+  // checkpoint pass: '' | 'en' | 'pair' ('' reads as English). Read-only — the
+  // editor never sends it. It is here so read-aloud can use the right voice on a
+  // document written in her own language.
+  doc_lang: DocLang
 }
 
+// The document-language verdict, shared by documents and garden cards. 'pair'
+// names the writer's own language rather than a language code, so changing her
+// pair re-reads her documents instead of stranding a stale name on them.
+export type DocLang = '' | 'en' | 'pair'
+
 // Fields the editor sends on auto-save. All optional so a rename can send title
 // alone; the editor sends the full set.
 export interface DocUpdate {
@@ -125,6 +135,9 @@ export interface VocabWord {
   phonetic: string
   example: string
   doc_id: string | null
+  // The language of the document this word was met in — the card's own language
+  // (migration 0018). Read-aloud needs it: "comum" is unguessable from letters.
+  lang: DocLang
   due_at: string
   interval_days: number
   ease: number
@@ -263,11 +276,34 @@ function signedOut(): UnauthorizedError {
   return new UnauthorizedError()
 }
 
-async function req<T>(path: string, init?: RequestInit): Promise<T> {
+// The document-language verdict is decided by the checkpoint pass, so the pass's
+// own response is the first moment the client can know it. It rides on a header
+// (the pass answers with a bare array of suggestions, and every caller reads it
+// as one), and reaches the app through a handler registered here — the same
+// shape onUnauthorized already uses, for the same reason: it is one fact from
+// deep inside a request that a component several layers up needs.
+//
+// Without it the editor learns the verdict only from a document save, which is
+// always one save behind the pass — and read-aloud is reached for precisely when
+// she has stopped typing and no further save is coming.
+let docLangHandler: ((docId: string, lang: DocLang) => void) | null = null
+
+export function onDocLang(handler: (docId: string, lang: DocLang) => void) {
+  docLangHandler = handler
+}
+
+// `verdictFor` names the document whose language this response may announce.
+// Only the three pass endpoints pass it; everything else has no verdict to carry
+// and never touches the handler.
+async function req<T>(path: string, init?: RequestInit, verdictFor?: string): Promise<T> {
   const res = await fetch(`/api${path}`, {
     headers: { 'Content-Type': 'application/json' },
     ...init,
   })
+  if (verdictFor && res.ok) {
+    const lang = res.headers.get('X-Petal-Doc-Lang')
+    if (lang === '' || lang === 'en' || lang === 'pair') docLangHandler?.(verdictFor, lang)
+  }
   if (res.status === 401) throw signedOut()
   if (!res.ok) {
     const detail = await res.text().catch(() => '')
@@ -309,14 +345,14 @@ export const api = {
   // Rate-limited per document server-side (returns the existing set if too soon).
   // Both passes return the UNIFIED pending set (grammar + voice), so the client
   // never drops one family's highlights when the other refreshes.
-  checkDoc: (id: string) => req<Suggestion[]>(`/docs/${id}/check`, { method: 'POST' }),
+  checkDoc: (id: string) => req<Suggestion[]>(`/docs/${id}/check`, { method: 'POST' }, id),
   // Voice-consistency pass: whole-document, explicit-action, slower. Returns the
   // unified pending set too. Rate-limited per document server-side.
-  voiceDoc: (id: string) => req<Suggestion[]>(`/docs/${id}/voice`, { method: 'POST' }),
+  voiceDoc: (id: string) => req<Suggestion[]>(`/docs/${id}/voice`, { method: 'POST' }, id),
   // Collocation coach: whole-document, explicit-action pass flagging non-native
   // word pairings ("do a decision" → "make a decision"). Returns the unified
   // pending set too. Rate-limited per document server-side.
-  collocationDoc: (id: string) => req<Suggestion[]>(`/docs/${id}/collocation`, { method: 'POST' }),
+  collocationDoc: (id: string) => req<Suggestion[]>(`/docs/${id}/collocation`, { method: 'POST' }, id),
   // Mechanics pass: persist the client-detected deterministic fixes as the
   // 'mechanics' family and return the unified pending set. Not rate-limited (it's
   // free, local detection); runs alongside the grammar checkpoint.

web/src/audio/speech.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
-import { nativeLang, speak, stopSpeech } from './speech'
+import { docLang, nativeLang, speak, stopSpeech } from './speech'
 import { resetPackForTests, setPackLang } from '../i18n'
 
 // Read-aloud has two jobs beyond "make a sound": ask for the right pace, and ask
@@ -85,3 +85,33 @@ describe('nativeLang', () => {
     expect(bodies.at(-1)).toMatchObject({ text: 'chat', lang: 'fr-FR' })
   })
 })
+
+describe('docLang', () => {
+  // The document's verdict is the answer for a passage lifted out of it, because
+  // for a Latin pair there is no other answer available: an English sentence and
+  // a Portuguese one are the same letters.
+  it('reads a flipped document in her own language', () => {
+    setPackLang('pt-PT')
+    expect(docLang('Ontem foi difícil.', 'pair')).toBe('pt-PT')
+  })
+
+  it('reads an English document in English, and treats the backfill as English', () => {
+    setPackLang('pt-PT')
+    expect(docLang('Yesterday was hard.', 'en')).toBe('en-US')
+    expect(docLang('Yesterday was hard.', '')).toBe('en-US')
+  })
+
+  it('lets the script win over the verdict, so quoted Chinese is never spelled out', () => {
+    // An English document quoting Chinese is 'en' by verdict, and the English
+    // voice reads Han characters one "Chinese letter" at a time — the one
+    // failure worse than silence.
+    setPackLang('zh')
+    expect(docLang('你好世界', 'en')).toBe('zh-CN')
+  })
+
+  it('is what the editor selection and the garden card ask for', () => {
+    setPackLang('fr')
+    speak('Le chat dort.', docLang('Le chat dort.', 'pair'))
+    expect(bodies.at(-1)).toMatchObject({ text: 'Le chat dort.', lang: 'fr-FR' })
+  })
+})

web/src/audio/speech.ts

@@ -90,6 +90,24 @@ export function nativeLang(): string {
   return pack().locale
 }
 
+// docLang turns a document-language verdict ('' | 'en' | 'pair', decided
+// server-side — see internal/suggestions/doclang.go) into a locale for a passage
+// taken out of that document. It is what the editor's read-aloud and the garden's
+// review card ask instead of guessing.
+//
+// The script test still wins, and that is not redundant with the verdict. A
+// Chinese sentence quoted inside an English document is 'en' by verdict and
+// still has to be read by the Chinese voice: the English voice spells Han
+// characters out one "Chinese letter" at a time, which is the one failure loud
+// enough to be worse than no audio. In the other direction there is nothing to
+// test — an English sentence inside Portuguese prose looks exactly like the
+// Portuguese around it — so the document's verdict is the only answer available,
+// and it is the answer this phase decided on.
+export function docLang(text: string, verdict: string): string {
+  if (CJK.test(text)) return 'zh-CN'
+  return verdict === 'pair' ? pack().locale : 'en-US'
+}
+
 // speak reads `text` aloud, cancelling anything already in flight so rapid taps
 // don't queue up. `lang` defaults to a guess from the text (Chinese vs English)
 // so callers can just pass the selection; pass an explicit locale to override.

web/src/components/Companion/PetalCompanion.tsx

@@ -88,13 +88,18 @@ export function PetalCompanion({
   const [pickerOpen, setPickerOpen] = useState(false)
   const rootRef = useRef<HTMLDivElement>(null)
   const badgeRef = useRef<HTMLButtonElement>(null)
+  // Stand-in for the badge's corner, used only for measuring — see
+  // useCardOverlap. It sits exactly where the badge sits but never bobs, shrinks
+  // or hovers, so what the mascot yields to can't depend on whether it is
+  // currently yielding.
+  const probeRef = useRef<HTMLSpanElement>(null)
 
   // When suggestion cards stack down into the corner, the kitten fades to
   // translucent and shrinks a step so the card stays readable and clickable.
   // It wakes back up whenever it has something to say (bubble) or is being
   // interacted with (picker open) — except under an open History or Garden
   // panel, where even a cheer would cover the controls she just reached for.
-  const crowded = useCardOverlap(badgeRef)
+  const crowded = useCardOverlap(probeRef)
   const faded = crowded.modal || (crowded.cards && !pickerOpen && !bubble)
 
   // Awake companions (no sleeping clip) don't visibly nap — when the engine
@@ -135,7 +140,7 @@ export function PetalCompanion({
   return (
     <div
       ref={rootRef}
-      className="pointer-events-none fixed bottom-4 right-4 z-40 flex flex-col items-end gap-2"
+      className="petal-corner pointer-events-none fixed bottom-4 right-4 z-40 flex flex-col items-end gap-2"
     >
       {pickerOpen && (
         <div
@@ -251,6 +256,16 @@ export function PetalCompanion({
         </div>
       )}
 
+      <span
+        ref={probeRef}
+        aria-hidden
+        className="pointer-events-none absolute bottom-0 right-0"
+        style={{
+          width: 'var(--petal-companion-size, 9rem)',
+          height: 'var(--petal-companion-size, 9rem)',
+        }}
+      />
+
       <button
         ref={badgeRef}
         type="button"

web/src/components/Companion/useCardOverlap.ts

@@ -1,4 +1,4 @@
-import { useEffect, useState, type RefObject } from 'react'
+import { useEffect, useRef, useState, type RefObject } from 'react'
 
 // How often to re-measure outside of scroll/resize events. Cards re-pack when
 // suggestions arrive, expand, or get accepted — none of which fire an event we
@@ -11,8 +11,20 @@ const POLL_MS = 500
 // means a future drawer is covered the day it's written, without a list to keep
 // in sync. Anything that doesn't actually reach the corner still won't trip the
 // rect test below.
+// How far a card must retreat before an already-yielded mascot comes back. Wide
+// enough to cover a re-pack or a browser bar appearing, small enough that a card
+// genuinely scrolled away still wakes it.
+const HOLD_PX = 24
+
 const CARD = '.petal-rail-card'
-const MODAL = '[role="dialog"][aria-modal="true"]'
+// The mobile sidebar drawer is named outright because it is the one overlay that
+// isn't a dialog. It slides over the page behind a scrim exactly as History and
+// Garden do, but it is the app's own navigation rather than something opened on
+// purpose, so it carries no modal role for the selector above to catch — and the
+// kitten sat in its bottom corner, over the last two rows of the language
+// picker. On a 390px phone that put "Español" and "I am learning Português"
+// under the halo: visibly there, and only partly tappable.
+const MODAL = '[role="dialog"][aria-modal="true"], .petal-sidebar.petal-drawer-open'
 
 export interface CardOverlap {
   // A suggestion card reaches the mascot. It should get out of the way, but may
@@ -25,11 +37,21 @@ export interface CardOverlap {
 }
 
 // Reports what, if anything, the mascot should yield to at the given element.
+//
+// Pass the probe span, never the badge itself. The badge shrinks when it yields
+// (.petal-companion-faded) and bobs continuously (petal-bob), and
+// getBoundingClientRect reports the *transformed* box — so measuring the badge
+// lets it shrink out of its own overlap test, wake up, overlap again, and pulse
+// forever against a card resting at its edge. The probe holds the corner box
+// still whatever the mascot is doing, which is what makes the test settle.
 // Used to fade the corner mascot out of the way when a card or panel reaches
 // into its corner, so nothing is ever hidden (or made unclickable) by the
 // kitten.
 export function useCardOverlap(ref: RefObject<HTMLElement | null>): CardOverlap {
   const [overlap, setOverlap] = useState<CardOverlap>({ cards: false, modal: false })
+  // check() runs on a timer and reads the previous answer, which state alone
+  // wouldn't hand it without re-subscribing every render.
+  const current = useRef(overlap)
 
   useEffect(() => {
     let raf = 0
@@ -38,16 +60,28 @@ export function useCardOverlap(ref: RefObject<HTMLElement | null>): CardOverlap
       const el = ref.current
       if (!el) return
       const r = el.getBoundingClientRect()
-      const hits = (selector: string) => {
+      // Cards settle a pixel or two from the corner all the time — the rail
+      // re-packs, the window resizes, a browser bar appears. Yielding is a
+      // visible move, so once yielded, hold it until the card has clearly gone:
+      // decide on a box grown by HOLD_PX rather than flipping on the exact edge.
+      const hits = (selector: string, held: boolean) => {
+        const pad = held ? HOLD_PX : 0
         for (const other of document.querySelectorAll(selector)) {
           const b = other.getBoundingClientRect()
-          if (b.left < r.right && b.right > r.left && b.top < r.bottom && b.bottom > r.top) {
+          if (
+            b.left < r.right + pad &&
+            b.right > r.left - pad &&
+            b.top < r.bottom + pad &&
+            b.bottom > r.top - pad
+          ) {
             return true
           }
         }
         return false
       }
-      const next = { cards: hits(CARD), modal: hits(MODAL) }
+      const prev = current.current
+      const next = { cards: hits(CARD, prev.cards), modal: hits(MODAL, prev.modal) }
+      current.current = next
       // Same-value object identity would re-render on every poll tick.
       setOverlap((prev) =>
         prev.cards === next.cards && prev.modal === next.modal ? prev : next,

web/src/components/Editor/AskPetal.tsx

@@ -5,12 +5,11 @@ import { splitBilingual } from './bilingualReply'
 import { fromIME } from '../../lib/ime'
 
 interface Props {
+  // The card's explanation is deliberately NOT passed in. Petal's opening
+  // bubble is that explanation rendered into the other half of the pair,
+  // fetched on open from this id — and when that can't be had, the panel has
+  // nothing to say rather than a second copy of the card.
   suggestionId: string
-  // The English explanation (shown in the card body). Petal's opening bubble is
-  // its translation into the pair language, fetched on open — so the panel
-  // doesn't just repeat the same English text twice. Falls back to this on
-  // failure.
-  explanation: string
 }
 
 // CJK fallback stack — Nunito has no Chinese glyphs, and on the zh pair both
@@ -44,10 +43,11 @@ const CHAT_MIN_PX = 160
 // conversation lives in this component's state — nothing is persisted; closing
 // the card (unmounting) clears it. Each send streams Petal's reply token-by-
 // token into the latest assistant bubble.
-export function AskPetal({ suggestionId, explanation }: Props) {
+export function AskPetal({ suggestionId }: Props) {
   const t = usePack()
-  // Opening bubble starts empty (caret-only) and fills with the pair-language
-  // translation once it lands; `seeding` drives that loading caret.
+  // Opening bubble starts empty (caret-only) and fills with the other half of
+  // the pair once it lands; `seeding` drives that loading caret, and the bubble
+  // goes away entirely if there turns out to be nothing to put in it.
   const [messages, setMessages] = useState<ChatMessage[]>([{ role: 'assistant', content: '' }])
   const [seeding, setSeeding] = useState(true)
   const [input, setInput] = useState('')
@@ -82,23 +82,31 @@ export function AskPetal({ suggestionId, explanation }: Props) {
     inputRef.current?.focus({ preventScroll: true })
   }, [])
 
-  // Fetch the pair-language translation of the explanation to seed the first
-  // bubble.
+  // Fetch the explanation rendered into the other half of her pair to seed the
+  // first bubble — English under a Portuguese card, her language under an
+  // English one; the server decides which way round (suggestions/translate.go).
   // Only replaces the seed bubble if the user hasn't started chatting yet (the
-  // conversation always opens with this one assistant turn). Falls back to the
-  // English explanation if the translation can't be fetched.
+  // conversation opens with this one assistant turn and nothing else).
+  //
+  // When it can't be fetched the panel opens empty rather than falling back to
+  // the explanation, which sits two lines higher in the card: a bubble that
+  // repeats the card verbatim reads as Petal answering in the language the tap
+  // was pressed to escape. Nothing to add, nothing shown.
   useEffect(() => {
     let cancelled = false
+    const seed = (text: string) =>
+      setMessages((prev) =>
+        prev.length !== 1 ? prev : text === '' ? [] : [{ role: 'assistant', content: text }],
+      )
     api
       .translateSuggestion(suggestionId)
       .then((res) => {
         if (cancelled) return
-        const text = res.translation.trim() || explanation
-        setMessages((prev) => (prev.length === 1 ? [{ role: 'assistant', content: text }] : prev))
+        seed(res.translation.trim())
       })
       .catch(() => {
         if (cancelled) return
-        setMessages((prev) => (prev.length === 1 ? [{ role: 'assistant', content: explanation }] : prev))
+        seed('')
       })
       .finally(() => {
         if (!cancelled) setSeeding(false)
@@ -106,7 +114,7 @@ export function AskPetal({ suggestionId, explanation }: Props) {
     return () => {
       cancelled = true
     }
-  }, [suggestionId, explanation])
+  }, [suggestionId])
 
   async function send() {
     const text = input.trim()

web/src/components/Editor/ChromeStrip.tsx

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useRef, useState } from 'react'
+import { useScrollEdge } from './useScrollEdge'
 
 // ChromeStrip is the row of document pills (tone, history, export) on a screen
 // too narrow to hold them. It scrolls within itself rather than letting the
@@ -15,7 +15,9 @@ import { useCallback, useEffect, useRef, useState } from 'react'
 // The fade is a mask rather than a gradient overlay so it works on whatever is
 // behind it (the cream page, the night theme, a falling petal) without knowing
 // the background colour.
-type Edge = 'none' | 'left' | 'right' | 'both'
+//
+// The measuring itself lives in useScrollEdge, shared with the formatting
+// toolbar — which has to say the same thing for the same reason.
 
 interface Props {
   className?: string
@@ -23,36 +25,7 @@ interface Props {
 }
 
 export function ChromeStrip({ className = '', children }: Props) {
-  const ref = useRef<HTMLDivElement>(null)
-  const [edge, setEdge] = useState<Edge>('none')
-
-  // A pixel of slack: scrollLeft is fractional under browser zoom and on
-  // high-DPI screens, so an exactly-scrolled-to-the-end strip can report
-  // something like 0.5px remaining and fade an edge that has nothing behind it.
-  const measure = useCallback(() => {
-    const el = ref.current
-    if (!el) return
-    const more = el.scrollWidth - el.clientWidth - el.scrollLeft > 1
-    const less = el.scrollLeft > 1
-    setEdge(less && more ? 'both' : less ? 'left' : more ? 'right' : 'none')
-  }, [])
-
-  useEffect(() => {
-    const el = ref.current
-    if (!el) return
-    measure()
-    el.addEventListener('scroll', measure, { passive: true })
-    // Both halves of "does it fit" can change without a scroll: the window
-    // resizes, or the labels themselves change when she switches her pair
-    // language and every pill in the row grows or shrinks at once.
-    const ro = new ResizeObserver(measure)
-    ro.observe(el)
-    for (const child of Array.from(el.children)) ro.observe(child)
-    return () => {
-      el.removeEventListener('scroll', measure)
-      ro.disconnect()
-    }
-  }, [measure])
+  const { ref, edge } = useScrollEdge<HTMLDivElement>()
 
   return (
     <div ref={ref} data-edge={edge} className={`petal-chrome-strip ${className}`}>

web/src/components/Editor/EditorCore.tsx

@@ -33,8 +33,8 @@ import { Composition } from './Composition'
 import { RewritePreview, type RewriteStatus } from './RewritePreview'
 import { planBatch } from './acceptBatch'
 import { entryId, idAfterRemoval, stepId, type Direction, type Span } from './triage'
-import { api, type Suggestion, type SuggestionType, type WordInfo } from '../../api/client'
-import { speak, speechSupported } from '../../audio/speech'
+import { api, type DocLang, type Suggestion, type SuggestionType, type WordInfo } from '../../api/client'
+import { docLang as docLocale, speak, speechSupported } from '../../audio/speech'
 import type { SpellChecker } from '../../hooks/useSpellChecker'
 import { fromIME } from '../../lib/ime'
 import type { Segmenter } from '../../lib/segment'
@@ -65,6 +65,13 @@ export interface EditorChange {
 interface Props {
   // Changing docId reloads the editor with that document's content.
   docId: string
+  // Which language this document is written in, as the server decided it
+  // ('' | 'en' | 'pair'). Read-aloud is the only thing here that reads it: a
+  // Portuguese selection has to be read by the Portuguese voice, and nothing in
+  // the letters says so. Updated by the server on save, so it trails a language
+  // flip by one auto-save — a passage read in the old voice once is the whole
+  // cost of not blocking the editor on a check.
+  docLang: DocLang
   initialContent: string
   onChange: (change: EditorChange) => void
   // LLM suggestions to highlight; accept/dismiss notify the parent for the API
@@ -255,6 +262,7 @@ interface RewriteState {
 // decoration layer. Hovering a highlight opens its SuggestionCard.
 export function EditorCore({
   docId,
+  docLang,
   initialContent,
   onChange,
   suggestions,
@@ -1098,7 +1106,17 @@ export function EditorCore({
           // actually knows (a real gloss or definition), so accidental lookups of
           // typos or proper nouns don't clutter the garden. Looking words up IS
           // the data source; this costs the writer nothing.
-          const known = !!info.gloss || info.definitions.length > 0
+          //
+          // "Knows" has to include the reverse reading, or a word of her own
+          // language can never be captured at all: the forward lookup of "carro"
+          // answers with nothing, and everything the card shows her comes out of
+          // `reverse`. Before Phase 28 that was academic, because every document
+          // was English; on a Portuguese document it silently emptied the garden
+          // of every word she actually met. Caught in a browser 2026-07-29 —
+          // right-clicking "carro" showed a full card and stored nothing.
+          const rev = info.reverse
+          const known =
+            !!info.gloss || info.definitions.length > 0 || !!rev?.gloss || (rev?.definitions?.length ?? 0) > 0
           // Reflect the saved state optimistically so the heart shows 💚 the
           // moment a known word loads, rather than flashing 🤍 until the capture
           // round-trips. vocabId is filled in when recordVocab returns.
@@ -1108,12 +1126,18 @@ export function EditorCore({
             .recordVocab({
               word: range.word,
               gloss: info.gloss,
-              definition: info.definitions[0]?.definition ?? '',
+              // `definition` is the English sense the review card falls back to
+              // when there is no gloss in her language — and for a word that *is*
+              // her language, the reverse gloss is exactly that: "carro" →
+              // "car; automobile; machine". The Portuguese monolingual definition
+              // underneath it explains the word in the language she already knows
+              // it in, which is not what a flashcard is for.
+              definition: info.definitions[0]?.definition ?? rev?.gloss ?? '',
               // The garden's pronunciation field holds whichever this word has:
               // IPA for an English word, pinyin for a Chinese one. Both answer
               // the same question on a review card — how do I say this — and a
               // second column would only be a second thing to keep in sync.
-              phonetic: pinyin || info.phonetic,
+              phonetic: pinyin || info.phonetic || rev?.phonetic || '',
               example,
               doc_id: docId,
             })
@@ -1532,8 +1556,10 @@ export function EditorCore({
           <SelectionBubble
             style={{ top: selection.top, left: selection.left, transform: 'translateY(calc(-100% - 8px))' }}
             onRewrite={handleRewrite}
-            onSpeak={speechSupported() ? () => speak(selection.text) : null}
-            onSpeakSlow={speechSupported() ? () => speak(selection.text, undefined, true) : null}
+            onSpeak={speechSupported() ? () => speak(selection.text, docLocale(selection.text, docLang)) : null}
+            onSpeakSlow={
+              speechSupported() ? () => speak(selection.text, docLocale(selection.text, docLang), true) : null
+            }
           />
         )}
         {rewrite && (
@@ -1556,6 +1582,7 @@ export function EditorCore({
             saved={wordInfo.saved}
             onToggleSave={toggleSaveWord}
             pinyin={wordInfo.pinyin}
+            lang={docLocale(wordInfo.word, docLang)}
             style={{ top: wordInfo.top, left: wordInfo.left }}
             onReplace={replaceWord}
           />

web/src/components/Editor/SuggestionCard.tsx

@@ -197,7 +197,7 @@ export function SuggestionCard({
         {asking ? 'Hide Petal' : 'Ask Petal ✨'}
       </button>
 
-      {asking && <AskPetal suggestionId={suggestion.id} explanation={suggestion.explanation} />}
+      {asking && <AskPetal suggestionId={suggestion.id} />}
 
       <div className="mt-3 flex items-center gap-2">
         {hasReplacement && (

web/src/components/Editor/SuggestionRail.tsx

@@ -217,7 +217,7 @@ const RailCard = forwardRef<HTMLDivElement, CardProps>(function RailCard(
         </span>
       </button>
 
-      {expanded && <AskPetal suggestionId={suggestion.id} explanation={suggestion.explanation} />}
+      {expanded && <AskPetal suggestionId={suggestion.id} />}
 
       <div className="mt-2.5 flex items-center gap-2">
         {hasReplacement && (

web/src/components/Editor/ToneSelect.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useRef, useState } from 'react'
+import { createPortal } from 'react-dom'
 
 import { usePack } from '../../i18n'
 import { useAnchoredMenu } from './anchoredMenu'
@@ -36,18 +37,20 @@ export function ToneSelect({ value, onChange }: Props) {
   const pk = usePack()
   const [open, setOpen] = useState(false)
   const ref = useRef<HTMLDivElement>(null)
-  const { triggerRef, style: menuStyle } = useAnchoredMenu(open, 200)
+  const { triggerRef, panelRef, style: menuStyle } = useAnchoredMenu(open, 200)
   const current = TONES.find((t) => t.value === value) ?? TONES[0]
 
-  // Click outside closes the menu.
+  // Click outside closes the menu. The list is portalled to <body>, so a tap on
+  // an option is not inside `ref` and has to be asked about separately.
   useEffect(() => {
     if (!open) return
     const onDown = (e: MouseEvent) => {
-      if (!ref.current?.contains(e.target as Node)) setOpen(false)
+      const target = e.target as Node
+      if (!ref.current?.contains(target) && !panelRef.current?.contains(target)) setOpen(false)
     }
     document.addEventListener('mousedown', onDown)
     return () => document.removeEventListener('mousedown', onDown)
-  }, [open])
+  }, [open, panelRef])
 
   return (
     <div ref={ref} className="shrink-0">
@@ -75,8 +78,10 @@ export function ToneSelect({ value, onChange }: Props) {
         </span>
       </button>
 
-      {open && (
+      {open &&
+        createPortal(
         <div
+          ref={panelRef}
           role="listbox"
           className="petal-word-card p-1.5"
           style={{
@@ -117,7 +122,8 @@ export function ToneSelect({ value, onChange }: Props) {
               </button>
             )
           })}
-        </div>
+        </div>,
+        document.body,
       )}
     </div>
   )

web/src/components/Editor/WordCard.tsx

@@ -22,11 +22,31 @@ interface Props {
   // is spelled in letters, and the slashes would say something untrue about it
   // in the one place a learner is looking for the truth about pronunciation.
   pinyin?: string
+  // The locale to pronounce the headword in — the document's language, decided
+  // by the caller (see docLang in audio/speech.ts).
+  //
+  // It has to be passed rather than guessed. `speak` falls back to detecting the
+  // script, and that test can only tell Han characters from letters: it reads
+  // "comum" and "casa" as English, so every read-aloud in a Portuguese document
+  // came out in the English voice. That is the same mistake the "also in" block
+  // below was built to avoid, arriving through the one button nobody had told
+  // about the document.
+  lang?: string
   style: React.CSSProperties
   onReplace: (synonym: string) => void
 }
 
-export function WordCard({ word, info, loading, saved, onToggleSave, pinyin, style, onReplace }: Props) {
+export function WordCard({
+  word,
+  info,
+  loading,
+  saved,
+  onToggleSave,
+  pinyin,
+  lang,
+  style,
+  onReplace,
+}: Props) {
   const t = usePack()
   const definitions = info?.definitions ?? []
   const synonyms = info?.synonyms ?? []
@@ -90,7 +110,7 @@ export function WordCard({ word, info, loading, saved, onToggleSave, pinyin, sty
             <>
               <button
                 type="button"
-                onClick={() => speak(word)}
+                onClick={() => speak(word, lang)}
                 aria-label={`Pronounce ${word}`}
                 title={t.editor.readAloud}
                 className="flex h-7 w-7 items-center justify-center rounded-full text-sm"
@@ -104,7 +124,7 @@ export function WordCard({ word, info, loading, saved, onToggleSave, pinyin, sty
                   slowing the tape, so it stays a voice rather than a groan. */}
               <button
                 type="button"
-                onClick={() => speak(word, undefined, true)}
+                onClick={() => speak(word, lang, true)}
                 aria-label={`Pronounce ${word} slowly`}
                 title={t.editor.readSlowly}
                 className="flex h-7 w-7 items-center justify-center rounded-full text-sm"

web/src/components/Editor/anchoredMenu.ts

@@ -6,15 +6,40 @@ import { useLayoutEffect, useRef, useState, type CSSProperties } from 'react'
 // button's wrapper, which was fine until that wrapper became ChromeStrip — a
 // horizontal scroller, and so a box that clips what overflows it. An absolute
 // menu inside it is 36px tall and scrolls away with the pills. Positioning the
-// menu against the viewport instead takes it out of the strip's hands entirely:
-// nothing clips a fixed box unless an ancestor has a transform, and none of the
-// editor's chrome does.
+// menu against the viewport instead takes it out of the strip's hands entirely.
+//
+// Or rather: it does once the menu is also *portalled out* of it, which is the
+// part this originally got wrong. `position: fixed` is only relative to the
+// viewport while no ancestor establishes a containing block for it — and a
+// `mask-image` does, exactly like a transform. Both scrollers fade their edges
+// with a mask (that is how each says "there is more this way"), so on any screen
+// narrow enough for the fade to appear — i.e. every phone — the menu was pulled
+// back inside the very box it was trying to escape: painted underneath the
+// toolbar, and untappable. It looked open and did nothing.
+//
+// So the panel is rendered through a portal into <body>. Nothing above it can
+// clip it, stack over it, or contain it, whatever the chrome does with masks
+// later. `panelRef` is returned for the outside-tap test, which can no longer
+// rely on the panel being a DOM descendant of the trigger's wrapper.
 //
 // The trade is that a fixed box doesn't follow its anchor, so anything that
 // moves the button — the page scrolling under it, the strip scrolling, the
 // window resizing — has to re-place the menu.
-export function useAnchoredMenu(open: boolean, width: number) {
-  const triggerRef = useRef<HTMLButtonElement>(null)
+//
+// The element type is a parameter because the two kinds of caller anchor
+// against different things: the tone and export pills hand it their own
+// <button>, while the toolbar's popovers anchor against the wrapper that holds
+// trigger and panel together (it is that wrapper an outside-tap test already
+// asks about, so measuring anything else would be a second source of truth).
+export function useAnchoredMenu<T extends HTMLElement = HTMLButtonElement>(
+  open: boolean,
+  width: number,
+) {
+  const triggerRef = useRef<T>(null)
+  // The portalled panel. Attach it to the element the style is spread onto, so
+  // an outside-tap test can ask "was this inside the menu?" of a node that is no
+  // longer beneath the trigger in the tree.
+  const panelRef = useRef<HTMLDivElement>(null)
   // Nothing to place before the first measurement; keeping it off-screen rather
   // than at 0,0 means no flash in the top-left corner on open.
   const [style, setStyle] = useState<CSSProperties>({ position: 'fixed', top: -9999, left: -9999 })
@@ -41,5 +66,5 @@ export function useAnchoredMenu(open: boolean, width: number) {
     }
   }, [open, width])
 
-  return { triggerRef, style }
+  return { triggerRef, panelRef, style }
 }

web/src/components/Editor/useScrollEdge.ts

@@ -0,0 +1,51 @@
+import { useCallback, useEffect, useRef, useState } from 'react'
+
+// Which end of a horizontal scroller has more behind it.
+//
+// Extracted from ChromeStrip when the formatting toolbar needed the same
+// answer. Both rows are in the same situation and it is a harsher one than most
+// scrollers face: the row is the *only* way to reach what is in it, so a control
+// that has scrolled out of sight is indistinguishable from a control that does
+// not exist. Fading the edge that has more behind it is the one cue that tells
+// those two apart.
+//
+// The caller owns the element and the styling; this hook only measures. Apply
+// the returned `edge` as a `data-edge` attribute and let CSS decide what a
+// faded edge looks like — the two rows sit on different backgrounds and mask
+// themselves at slightly different insets.
+export type Edge = 'none' | 'left' | 'right' | 'both'
+
+export function useScrollEdge<T extends HTMLElement = HTMLDivElement>() {
+  const ref = useRef<T>(null)
+  const [edge, setEdge] = useState<Edge>('none')
+
+  // A pixel of slack: scrollLeft is fractional under browser zoom and on
+  // high-DPI screens, so an exactly-scrolled-to-the-end strip can report
+  // something like 0.5px remaining and fade an edge that has nothing behind it.
+  const measure = useCallback(() => {
+    const el = ref.current
+    if (!el) return
+    const more = el.scrollWidth - el.clientWidth - el.scrollLeft > 1
+    const less = el.scrollLeft > 1
+    setEdge(less && more ? 'both' : less ? 'left' : more ? 'right' : 'none')
+  }, [])
+
+  useEffect(() => {
+    const el = ref.current
+    if (!el) return
+    measure()
+    el.addEventListener('scroll', measure, { passive: true })
+    // Both halves of "does it fit" can change without a scroll: the window
+    // resizes, or the labels themselves change when she switches her pair
+    // language and every control in the row grows or shrinks at once.
+    const ro = new ResizeObserver(measure)
+    ro.observe(el)
+    for (const child of Array.from(el.children)) ro.observe(child)
+    return () => {
+      el.removeEventListener('scroll', measure)
+      ro.disconnect()
+    }
+  }, [measure])
+
+  return { ref, edge }
+}

web/src/components/Export/ExportMenu.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useRef, useState } from 'react'
+import { createPortal } from 'react-dom'
 import { api, type ExportFormat } from '../../api/client'
 import { usePack } from '../../i18n'
 import { useAnchoredMenu } from '../Editor/anchoredMenu'
@@ -29,16 +30,20 @@ export function ExportMenu({ docId }: Props) {
   const t = usePack()
   const [open, setOpen] = useState(false)
   const ref = useRef<HTMLDivElement>(null)
-  const { triggerRef, style: menuStyle } = useAnchoredMenu(open, 220)
+  const { triggerRef, panelRef, style: menuStyle } = useAnchoredMenu(open, 220)
 
+  // The menu is portalled to <body>, so a tap on a format is outside `ref` and
+  // has to be asked about separately or it would close the menu instead of
+  // exporting.
   useEffect(() => {
     if (!open) return
     const onDown = (e: MouseEvent) => {
-      if (!ref.current?.contains(e.target as Node)) setOpen(false)
+      const target = e.target as Node
+      if (!ref.current?.contains(target) && !panelRef.current?.contains(target)) setOpen(false)
     }
     document.addEventListener('mousedown', onDown)
     return () => document.removeEventListener('mousedown', onDown)
-  }, [open])
+  }, [open, panelRef])
 
   return (
     <div ref={ref} className="shrink-0">
@@ -63,8 +68,10 @@ export function ExportMenu({ docId }: Props) {
         <span style={{ color: 'var(--color-muted)' }}>· Export</span>
       </button>
 
-      {open && (
+      {open &&
+        createPortal(
         <div
+          ref={panelRef}
           role="menu"
           className="petal-word-card p-1.5"
           style={{
@@ -116,7 +123,8 @@ export function ExportMenu({ docId }: Props) {
               Print / PDF
             </span>
           </button>
-        </div>
+        </div>,
+        document.body,
       )}
     </div>
   )

web/src/components/Garden/GardenPanel.tsx

@@ -1,6 +1,6 @@
 import { useCallback, useEffect, useMemo, useState } from 'react'
 import { api, type VocabGrade, type VocabWord } from '../../api/client'
-import { speak, speechSupported, stopSpeech } from '../../audio/speech'
+import { docLang as docLocale, speak, speechSupported, stopSpeech } from '../../audio/speech'
 import { useFocusTrap } from '../../hooks/useFocusTrap'
 import { usePack, type Line } from '../../i18n'
 import { JournalView } from './JournalView'
@@ -314,7 +314,21 @@ function GardenView({
                       {blossom(w.reps)}
                     </span>
                     <span className="flex min-w-0 flex-1 flex-col">
+                      <span className="flex min-w-0 items-center gap-1.5">
                         <span className="truncate text-sm font-bold text-plum">{w.word}</span>
+                        {/* Only a card in her own language is marked. An English
+                            garden with a badge on every blossom would be a
+                            garden with no badges at all; the marker exists so
+                            the rare Portuguese word is legible among them. */}
+                        {w.lang === 'pair' && (
+                          <span
+                            className="shrink-0 rounded-full px-1.5 py-0.5 text-[9px] font-bold lowercase"
+                            style={{ background: 'var(--color-surface-alt)', color: 'var(--color-muted)' }}
+                          >
+                            {t.nativeName}
+                          </span>
+                        )}
+                      </span>
                       {(w.gloss || w.definition) && (
                         <span
                           className="truncate text-xs"
@@ -354,7 +368,7 @@ function GardenView({
                         {speechSupported() && (
                           <button
                             type="button"
-                            onClick={() => speak(w.word)}
+                            onClick={() => speak(w.word, docLocale(w.word, w.lang))}
                             className="rounded-full px-2.5 py-1 text-xs font-semibold"
                             style={{ background: 'var(--color-surface-alt)' }}
                           >
@@ -477,7 +491,7 @@ function ReviewSession({
                 <>
                   <button
                     type="button"
-                    onClick={() => speak(card.word)}
+                    onClick={() => speak(card.word, docLocale(card.word, card.lang))}
                     aria-label={`Pronounce ${card.word}`}
                     className="flex h-6 w-6 items-center justify-center rounded-full text-xs"
                     style={{ background: 'var(--color-surface)' }}
@@ -488,7 +502,7 @@ function ReviewSession({
                       worth hearing stretched out. */}
                   <button
                     type="button"
-                    onClick={() => speak(card.word, undefined, true)}
+                    onClick={() => speak(card.word, docLocale(card.word, card.lang), true)}
                     aria-label={`Pronounce ${card.word} slowly`}
                     title={t.garden.readSlowly}
                     className="flex h-6 w-6 items-center justify-center rounded-full text-xs"

web/src/components/Toolbar/Toolbar.tsx

@@ -1,7 +1,10 @@
 import type { Editor } from '@tiptap/react'
 import { useEditorState } from '@tiptap/react'
 import { useEffect, useRef, useState } from 'react'
+import { createPortal } from 'react-dom'
 import { uploadImageInto } from '../Editor/EditorCore'
+import { useAnchoredMenu } from '../Editor/anchoredMenu'
+import { useScrollEdge } from '../Editor/useScrollEdge'
 import { usePack } from '../../i18n'
 
 interface Props {
@@ -56,9 +59,26 @@ const Divider = () => (
   <span className="mx-1 h-5 w-px" style={{ background: 'var(--color-border)' }} />
 )
 
-// A popover anchored under its trigger. The trigger + panel share a relative
-// wrapper; `open`/`onClose` are owned by the toolbar so only one is open at once.
-// A pointer-down outside the wrapper closes it.
+// A popover anchored under its trigger. The trigger + panel share a wrapper;
+// `open`/`onClose` are owned by the toolbar so only one is open at once. A
+// pointer-down outside the wrapper closes it.
+//
+// The panel is placed in viewport coordinates rather than absolutely inside
+// that wrapper, for the same two reasons ChromeStrip's menus were (see
+// useAnchoredMenu) — and on a phone both of them bite at once:
+//
+//   * The toolbar clips what overflows it. On a desktop that clip is lifted on
+//     hover, which is where an absolutely-positioned panel got away with it for
+//     as long as it did; a touchscreen never hovers, so tapping A or H opened a
+//     panel that was simply not on the screen. The button lit up and nothing
+//     else happened, which is the worst shape a bug can take — it reads as the
+//     feature not existing.
+//   * `left-0` hangs a 200px panel off the right edge of a 390px phone when its
+//     trigger sits near the end of the row. useAnchoredMenu clamps it back
+//     inside the window instead.
+//
+// The panel stays a DOM child of the wrapper (fixed, not portalled) so the
+// outside-tap test below keeps working on containment alone.
 function Popover({
   open,
   onClose,
@@ -72,23 +92,27 @@ function Popover({
   children: React.ReactNode
   width?: number
 }) {
-  const ref = useRef<HTMLDivElement>(null)
+  const { triggerRef: ref, panelRef, style } = useAnchoredMenu<HTMLDivElement>(open, width)
   useEffect(() => {
     if (!open) return
     const onDown = (e: MouseEvent) => {
-      if (!ref.current?.contains(e.target as Node)) onClose()
+      const target = e.target as Node
+      // The panel is portalled to <body>, so "inside" is either half.
+      if (!ref.current?.contains(target) && !panelRef.current?.contains(target)) onClose()
     }
     document.addEventListener('mousedown', onDown)
     return () => document.removeEventListener('mousedown', onDown)
-  }, [open, onClose])
+  }, [open, onClose, ref, panelRef])
   return (
-    <div ref={ref} className="relative flex items-center">
+    <div ref={ref} className="flex items-center">
       {trigger}
-      {open && (
+      {open &&
+        createPortal(
           <div
-          className="absolute left-0 top-full z-40 mt-1.5 p-2"
+            ref={panelRef}
+            className="p-2"
             style={{
-            width,
+              ...style,
               borderRadius: 'var(--radius-card)',
               background: 'var(--color-surface)',
               border: '1px solid var(--color-border)',
@@ -96,7 +120,8 @@ function Popover({
             }}
           >
             {children}
-        </div>
+          </div>,
+          document.body,
         )}
     </div>
   )
@@ -175,6 +200,10 @@ export function Toolbar({ editor, onVoiceCheck, voicing, onCollocationCheck, col
   const [menu, setMenu] = useState<'color' | 'highlight' | 'size' | 'link' | 'table' | 'outline' | null>(null)
   const [linkUrl, setLinkUrl] = useState('')
   const fileInputRef = useRef<HTMLInputElement>(null)
+  // Which end of the row still has controls behind it. Only ever visible on a
+  // coarse pointer, where the row scrolls instead of expanding on hover — see
+  // the .petal-toolbar rules in index.css.
+  const { ref: toolbarRef, edge } = useScrollEdge<HTMLDivElement>()
 
   const state = useEditorState({
     editor,
@@ -255,6 +284,8 @@ export function Toolbar({ editor, onVoiceCheck, voicing, onCollocationCheck, col
 
   return (
     <div
+      ref={toolbarRef}
+      data-edge={edge}
       className="petal-toolbar mb-4 flex items-center gap-0.5 self-start px-2 py-1.5"
       style={{
         borderRadius: 'var(--radius-card)',

web/src/hooks/useAutoSave.ts

@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useRef, useState } from 'react'
-import { api, UnauthorizedError, type DocUpdate } from '../api/client'
+import { api, UnauthorizedError, type Document, type DocUpdate } from '../api/client'
 import { clearDraft, stashDraft } from '../lib/drafts'
 
 export type SaveStatus = 'idle' | 'pending' | 'saving' | 'saved' | 'error' | 'signed-out'
@@ -10,7 +10,14 @@ const SAVED_FADE_MS = 3000
 // useAutoSave debounces document saves. Call schedule() on every edit; it fires
 // PUT /api/docs/:id 1.5s after the last change. status drives the StatusBar:
 // pending → saving → saved (fades to idle after 3s).
-export function useAutoSave(docId: string | null) {
+//
+// `onSaved` receives the row the server wrote back. The save response used to be
+// discarded, which was fine while every field in it was one the client had just
+// sent — and stopped being fine when `doc_lang` arrived, a field only the server
+// can decide. Without this the verdict reached the editor on open and never
+// again, so a document that turned Portuguese while she typed went on being read
+// aloud in English until the next reload.
+export function useAutoSave(docId: string | null, onSaved?: (doc: Document) => void) {
   const [status, setStatus] = useState<SaveStatus>('idle')
 
   const debounceRef = useRef<ReturnType<typeof setTimeout>>(undefined)
@@ -25,6 +32,11 @@ export function useAutoSave(docId: string | null) {
   // the loop stops here and the writing waits in localStorage instead.
   const signedOutRef = useRef(false)
 
+  // Read through a ref so a caller passing an inline arrow doesn't have to
+  // memoize it to keep flush stable.
+  const onSavedRef = useRef(onSaved)
+  onSavedRef.current = onSaved
+
   const flush = useCallback(async () => {
     const id = docIdRef.current
     const body = pendingRef.current
@@ -39,7 +51,8 @@ export function useAutoSave(docId: string | null) {
 
     setStatus('saving')
     try {
-      await api.updateDoc(id, body)
+      const saved = await api.updateDoc(id, body)
+      onSavedRef.current?.(saved)
       clearDraft(id) // it's on the server now; the rescue copy is redundant
       setStatus('saved')
       clearTimeout(fadeRef.current)

web/src/i18n/packs/pt-PT.ts

@@ -42,6 +42,25 @@ export const ptPT: Pack = {
   nativeName: 'Português',
   locale: 'pt-PT',
 
+  // pt-PT is the second pair Petal can be *learned* toward: spaces do the
+  // segmenting a Latin script needs, and dict.db already reads Portuguese into
+  // English (see auth.learnerPairs for both halves of that argument).
+  //
+  // Each label is written for whoever would pick it, which is why they are not
+  // in the same language as each other. A native Portuguese speaker practising
+  // English reads the first; an English speaker learning Portuguese reads the
+  // second, and would not be helped by being told "Português" in Portuguese.
+  //
+  // This is also the switch that decides which language Petal *explains* in, so
+  // it is the difference between a Portuguese document annotated in Portuguese
+  // and the same document annotated in English.
+  learner: {
+    label: 'Estou a aprender · I am learning',
+    toEn: 'inglês',
+    toPair: 'Portuguese',
+    failed: 'Não foi possível mudar · Couldn’t switch — nothing changed',
+  },
+
   app: {
     duplicateTitle: (title) => `${title} (cópia)`,
     garden: 'Jardim de palavras',

web/src/index.css

@@ -422,10 +422,15 @@ button, a, input {
 /* --- Companion kitten -------------------------------------------------------
    The cozy corner mascot. Gently bobs while awake, settles and sways slowly
    while napping; its speech bubble pops in; little zzz drift up when asleep. */
-.petal-companion {
+/* The whole corner, badge and bubble and measuring probe alike. The size lives
+   here rather than on the badge so the probe — a sibling, not a child — is sized
+   from the same number the mascot is. */
+.petal-corner {
   /* Mascot size scales with the viewport width: ~original on a laptop, up to
      ~2× on a large desktop. Tune the middle (vw) term to taste. */
   --petal-companion-size: clamp(9rem, 15.3vw, 18rem);
+}
+.petal-companion {
   animation: petal-bob 3.2s ease-in-out infinite;
   /* Shrink toward its corner when fading out of a card's way. `scale` is a
      separate property from `transform` so it composes with the bob keyframes. */
@@ -559,6 +564,64 @@ button, a, input {
     padding-top: 0.25rem;
     padding-bottom: 0.25rem;
   }
+
+  /* The formatting toolbar reaches everything it holds by expanding on hover
+     (see .petal-toolbar above). A touchscreen never hovers, so that rule never
+     fired here and the row stayed clipped at `overflow: hidden` for good: on a
+     390px phone roughly 750px of it — every heading, both lists, all three
+     alignments, link, image, table, outline, and both AI passes — could not be
+     reached at all. The faded edge said "there is more this way" and there was
+     no way.
+
+     So on a coarse pointer the row does what the pill strip does one line
+     above it: keeps every control and scrolls sideways, but only itself.
+     overscroll-behavior stops a swipe that runs out of buttons from dragging
+     the page of writing along with it, and the scrollbar is hidden because a
+     half-visible button at the edge is the affordance. The panels that hang off
+     these buttons are placed in viewport coordinates (see Popover in
+     Toolbar.tsx), so nothing here clips them. */
+  .petal-toolbar {
+    overflow-x: auto;
+    overflow-y: hidden;
+    overscroll-behavior-x: contain;
+    scrollbar-width: none;
+    -ms-overflow-style: none;
+    -webkit-mask-image: none;
+    mask-image: none;
+  }
+  .petal-toolbar::-webkit-scrollbar {
+    display: none;
+  }
+  /* :hover can still be reported on a touchscreen — a tap leaves a lingering
+     hover state on the last thing touched — and the desktop rule would answer
+     it by unwrapping the row mid-scroll. Hold the scrolling shape instead. */
+  .petal-toolbar:hover,
+  .petal-toolbar:focus-within {
+    flex-wrap: nowrap;
+    overflow-x: auto;
+    overflow-y: hidden;
+  }
+  /* Which edge has more behind it, from the same measurement the pill strip
+     uses (useScrollEdge → data-edge). A row whose buttons all fit is left
+     unmasked, so the fade only ever appears when it means something. */
+  .petal-toolbar[data-edge='right'] {
+    -webkit-mask-image: linear-gradient(to right, #000 92%, transparent 100%);
+    mask-image: linear-gradient(to right, #000 92%, transparent 100%);
+  }
+  .petal-toolbar[data-edge='left'] {
+    -webkit-mask-image: linear-gradient(to left, #000 92%, transparent 100%);
+    mask-image: linear-gradient(to left, #000 92%, transparent 100%);
+  }
+  .petal-toolbar[data-edge='both'] {
+    -webkit-mask-image: linear-gradient(
+      to right,
+      transparent 0%,
+      #000 8%,
+      #000 92%,
+      transparent 100%
+    );
+    mask-image: linear-gradient(to right, transparent 0%, #000 8%, #000 92%, transparent 100%);
+  }
 }
 
 /* --- Responsive sidebar (narrow screens) ------------------------------------
@@ -599,6 +662,17 @@ button, a, input {
     z-index: 20;
     background: rgba(61, 46, 57, 0.18);
   }
+
+  /* Sit the mascot above the status bar rather than on top of it.
+     --petal-companion-size bottoms out at 9rem, which is most of a phone's
+     width, and at `bottom-4` the bottom of that circle lands inside the 2.75rem
+     status bar — directly over "Hide falling petals", which could not be tapped
+     at all. The kitten yields to cards and panels (useCardOverlap) but the
+     status bar is neither: it is always there, so yielding to it would mean
+     fading forever. Moving up once is the honest fix. */
+  .petal-corner {
+    bottom: calc(2.75rem + 0.5rem);
+  }
 }
 
 /* Small phones only: see the header in App.tsx for why the wordmark yields.