diff --git a/web/src/App.tsx b/web/src/App.tsx
index 65fe344..1917177 100644
--- a/web/src/App.tsx
+++ b/web/src/App.tsx
@@ -81,7 +81,18 @@ export default function App() {
     return wordCountRef.current === 0 && (t === '' || t === 'Untitled')
   }, [])
 
-  const { status, schedule, saveNow } = useAutoSave(currentDoc?.id ?? null)
+  // 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
diff --git a/web/src/hooks/useAutoSave.ts b/web/src/hooks/useAutoSave.ts
index 8d0eb3a..de95ccb 100644
--- a/web/src/hooks/useAutoSave.ts
+++ b/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)