Merge branch 'fix/review-2175' into chore/electron-0.5.4

CHANGELOG.md

@@ -16,6 +16,7 @@ the frozen-backend fallback mirror it for their toolchains.
 
 ### Fixed
 
+- Name the voice profile when its saved language is one the active engine can't speak, instead of advising a language picker already set to Auto (#2175, #2156) — thanks @shivsin25!
 - Validate Python dependencies before reusing a desktop runtime and offer setup for incomplete environments (#2176)
 - Check active model cloning support before starting voice conversion (#2147)
 - Accept both valid SIGKILL diagnostics in the desktop lifecycle regression check (#2170)

backend/api/routers/generation.py

@@ -143,7 +143,7 @@ def _resolve_profile_conditioning(row, *, ref_text=None, instruct=None,
     out = {
         "ref_audio_path": None, "ref_text": ref_text, "instruct": instruct,
         "seed": seed, "language": language, "kind": None,
-        "persist_ref_text": False,
+        "persist_ref_text": False, "language_from_profile": False,
     }
     # `kind` is authoritative (0005): 'design' profiles condition on their
     # deterministic rendered sample + instruct; 'clone' on the user's
@@ -212,6 +212,12 @@ def _resolve_profile_conditioning(row, *, ref_text=None, instruct=None,
             prof_lang = None
         if prof_lang and prof_lang != "Auto":
             out["language"] = prof_lang
+            # #2156: record that the caller never asked for this language. The
+            # UI omits `language` entirely while its picker reads "Auto", so a
+            # profile-filled language must not be reported back as if the user
+            # had picked it — an engine that can't speak it would otherwise
+            # tell them to "leave language as Auto", which is what they did.
+            out["language_from_profile"] = True
     return out
 
 
@@ -1043,6 +1049,18 @@ _LANGUAGE_REJECTION_SIGNATURES = (
     "unsupported language code",
 )
 
+# Engine-specific rejections that ALREADY name the engine and what it supports,
+# so #1257's generic rewrite deliberately leaves them alone — re-wrapping them
+# only nests "Engine's own message:" twice. They still have to be recognised as
+# language rejections for #2156's provenance check, which cares about the
+# *cause* of the language, not the quality of the wording.
+_SELF_DESCRIBING_LANGUAGE_REJECTIONS = (
+    # services/tts_backend.py: "…doesn't support language='Persian'. Kokoro
+    # supports: …" — mlx-audio's Kokoro, the engine reported in #2156.
+    "doesn't support language",
+    "does not support language",
+)
+
 #: `unsupported language: xx` / `unsupported language 'xx'` — but not
 #: `unsupported language model ...`.
 _LANGUAGE_REJECTION_RE = re.compile(
@@ -1052,15 +1070,87 @@ _LANGUAGE_REJECTION_RE = re.compile(
 )
 
 
+def _is_language_rejection(text: str) -> bool:
+    """True when an engine failure is about the LANGUAGE it was handed.
+
+    Matched on the message, not the type: the engines multiplex third-party
+    libraries that each raise their own class. Covers the self-describing
+    wordings too — #1257's rewrite skips those, but #2156 still needs to know a
+    language was refused so it can say where that language came from.
+    """
+    low = text.lower()
+    return (
+        any(sig in low for sig in _LANGUAGE_REJECTION_SIGNATURES)
+        or any(sig in low for sig in _SELF_DESCRIBING_LANGUAGE_REJECTIONS)
+        or bool(_LANGUAGE_REJECTION_RE.search(text))
+    )
+
+
+def _profile_language_rejection_detail(exc: BaseException, language) -> str:
+    """The 400 body for a language the *voice profile* supplied, not the user.
+
+    #2156: the UI omits `language` while its picker reads "Auto", and #533
+    fills that gap from the selected profile. When the active engine can't
+    speak the profile's language the engine's own message tells the user to
+    "leave language as 'Auto'" — which is exactly what they did, so the advice
+    cannot be acted on. Name the real source and the remedies that exist.
+    """
+    return (
+        f"This voice profile is saved with the language '{language}', and the "
+        f"active engine can't speak it. The language picker being on \"Auto\" "
+        f"does not override that — Auto fills the language in from the "
+        f"profile. Set this voice profile's language to one the engine "
+        f"supports, pick a supported language explicitly for this render, or "
+        f"switch engine in Model Catalogue (the VoiceStudio engine has the "
+        f"widest coverage). Engine's own message: {exc}"
+    )
+
+
+def _language_rejection_payload(exc, language, *, from_profile):
+    """Stable, non-retryable error metadata for both response transports."""
+    from core.public_errors import stream_failure
+    failure = stream_failure("invalid_request")
+    failure["terminal"] = True
+    if from_profile:
+        failure.update(
+            code="profile_language_rejected", language=language,
+            detail=_profile_language_rejection_detail(_root_language_error(exc), language),
+        )
+    return failure
+
+
+def _language_rejection_http_error(exc: BaseException, language, *, from_profile):
+    """The 400 a refused language deserves, wherever the refusal was raised.
+
+    A language an engine cannot speak is never retryable — not by waiting, and
+    not by re-running the same request on another machine. Built here so the
+    local (`ValueError`) and remote (`RemoteJobFailed`) handlers cannot drift:
+    #2156 shipped the profile-aware branch on the local path only, and a remote
+    render kept answering with a retryable 503 that offered "run it on this
+    machine instead", which cannot help.
+    """
+    root = _root_language_error(exc)
+    detail = (
+        _profile_language_rejection_detail(root, language)
+        if from_profile else str(exc)
+    )
+    if from_profile:
+        detail = {"code": "profile_language_rejected", "language": language, "message": detail}
+    return HTTPException(status_code=400, detail=detail)
+
+
 def _language_rejection_or(e: BaseException, backend, language):
     """``e`` rewritten with engine context when it's a language rejection.
 
     Returns ``e`` unchanged otherwise, so this is safe to wrap any failure in.
-    Matched on the message, not the type: the engines multiplex third-party
-    libraries that each raise their own class.
+    Deliberately narrower than :func:`_is_language_rejection`: a message that
+    already names its engine and the languages it supports is left alone rather
+    than nested inside a second "Engine's own message:".
     """
     text = str(e)
     low = text.lower()
+    if any(sig in low for sig in _SELF_DESCRIBING_LANGUAGE_REJECTIONS):
+        return e
     if not any(sig in low for sig in _LANGUAGE_REJECTION_SIGNATURES) and not (
         _LANGUAGE_REJECTION_RE.search(text)
     ):
@@ -1069,13 +1159,23 @@ def _language_rejection_or(e: BaseException, backend, language):
         type(backend), "id", type(backend).__name__
     )
     requested = f" '{language}'" if language else ""
-    return ValueError(
+    rewritten = ValueError(
         f"The {engine} engine can't speak{requested}. VoiceStudio offers every "
         f"language its default engine supports, but each engine covers a "
         f"different set — pick one this engine supports, or switch engine in "
         f"Model Catalogue (the VoiceStudio engine has the widest coverage) "
         f"and generate again. Engine's own message: {e}"
     )
+    # Keep the engine's own text reachable. #2156's profile message quotes the
+    # engine once; without this it would quote THIS wrapper, repeating both the
+    # engine-switch remedy and "Engine's own message:" twice.
+    rewritten.engine_language_error = e
+    return rewritten
+
+
+def _root_language_error(exc: BaseException) -> BaseException:
+    """The engine's own rejection, unwrapping :func:`_language_rejection_or`."""
+    return getattr(exc, "engine_language_error", exc)
 
 
 def _persist_profile_ref_text(profile_id: str, ref_text: str) -> None:
@@ -1570,6 +1670,9 @@ async def generate_speech(
     ref_lease = None
     used_seed = seed
     resolved_profile_id = None
+    # #2156: True once a profile's stored language fills a language the caller
+    # never sent, so a rejection can name the profile instead of the picker.
+    language_from_profile = False
     history_mode = None  # profile.kind when a profile drives; else inferred at insert
     # #1032: profile id to persist an auto-transcribed reference transcript to.
     # Set only for a plain (unlocked) clone profile whose stored ref_text is
@@ -1598,6 +1701,7 @@ async def generate_speech(
             instruct = _cond["instruct"]
             used_seed = _cond["seed"]
             language = _cond["language"]
+            language_from_profile = _cond["language_from_profile"]
             if _cond["persist_ref_text"]:
                 persist_ref_text_profile_id = profile_id
     elif ref_audio is not None:
@@ -1872,10 +1976,14 @@ async def generate_speech(
                 # holding what is often its only slot until the lease lapses.
                 render.cancel()
                 raise
-            except ValueError:
+            except ValueError as e:
                 logger.error("Remote generation request rejected")
                 from core.public_errors import stream_failure
-                yield _line({"type": "error", **stream_failure("invalid_request")})
+                failure = (
+                    _language_rejection_payload(e, language, from_profile=language_from_profile)
+                    if _is_language_rejection(str(e)) else stream_failure("invalid_request")
+                )
+                yield _line({"type": "error", **failure})
             except gpu_gateway.ModelNotDownloaded as e:
                 logger.warning("Remote model missing on %s", _target_label)
                 from core.public_errors import stream_failure
@@ -1891,11 +1999,14 @@ async def generate_speech(
             except gpu_gateway.RemoteJobFailed as e:
                 logger.error("Remote generate failed on %s", _target_label)
                 from core.public_errors import stream_failure
+                if _is_language_rejection(str(e)):
+                    yield _line({"type": "error", **_language_rejection_payload(
+                        e, language, from_profile=language_from_profile,
+                    )})
+                else:
                     yield _line({
-                    "type": "error",
-                    **stream_failure("generation_failed"),
-                    "retryable": True,
-                    "target_label": e.worker_label or _target_label,
+                        "type": "error", **stream_failure("generation_failed"),
+                        "retryable": True, "target_label": e.worker_label or _target_label,
                         "hint": e.hint,
                     })
             except Exception as exc:
@@ -2206,10 +2317,14 @@ async def generate_speech(
                 failure = stream_failure("generation_timeout")
                 failure["retry_after"] = 30
                 yield _line({"type": "error", **failure})
-            except ValueError:
+            except ValueError as e:
                 logger.error("Streaming generation request rejected")
                 from core.public_errors import stream_failure
-                yield _line({"type": "error", **stream_failure("invalid_request")})
+                failure = (
+                    _language_rejection_payload(e, language, from_profile=language_from_profile)
+                    if _is_language_rejection(str(e)) else stream_failure("invalid_request")
+                )
+                yield _line({"type": "error", **failure})
             except Exception as exc:
                 # A streaming request answers 200 and carries its failure as an
                 # in-band error frame, so it never reaches the global 500
@@ -2392,6 +2507,15 @@ async def generate_speech(
         # the client can offer "run it on this machine instead" — a resubmit
         # the user chose, with a wait they were told about.
         logger.error("Remote generate failed on %s: %s", _target_label, e)
+        # #2156: a language the engine can't speak is a request problem, not a
+        # worker problem. It travels home as RemoteJobFailed — caught here,
+        # ahead of the ValueError branch below — so without this the user is
+        # told to retry on this machine, where the same engine refuses the same
+        # language. Answer it as the 400 it is, on either path.
+        if _is_language_rejection(str(e)):
+            raise _language_rejection_http_error(
+                e, language, from_profile=language_from_profile
+            ) from e
         raise HTTPException(
             status_code=503,
             detail=f"{e} {e.hint or 'Run it on this machine instead, or pick another GPU.'}",
@@ -2426,6 +2550,15 @@ async def generate_speech(
         raise HTTPException(status_code=503, detail=str(e)) from e
     except ValueError as e:
         logger.error("Validation failed: %s", e)
+        # #2156: the language the engine refused was never chosen by the user —
+        # it came from the selected voice profile because the picker was on
+        # "Auto". The engine's own remedy ("leave language as 'Auto'") is then
+        # unfollowable, so say where the language actually came from. Only this
+        # scope knows that; the engine adapters never see the provenance.
+        if language_from_profile and _is_language_rejection(str(e)):
+            raise _language_rejection_http_error(
+                e, language, from_profile=True
+            ) from e
         # Most ValueErrors here are VoiceStudio's own validation messages and
         # are exactly what the user should read. A few are raw library text
         # naming parameters and files the user cannot act on — those get the

docs/engines/mlx-audio.md

@@ -54,7 +54,14 @@ HF repo id. The env var overrides the persisted UI choice.
 - Language support is per-model (Kokoro ~8 languages, others vary). An
   unsupported language for Kokoro produces a clear error naming what it
   does support ([#977](https://github.com/debpalash/VoiceStudio/issues/977))
-  — leave language on Auto or switch to a multilingual engine.
+  — pick a language it supports or switch to a multilingual engine.
+- Auto is not an escape hatch from that. With the picker on Auto the request
+  carries no language, and a selected voice profile's saved language fills the
+  gap ([#533](https://github.com/debpalash/VoiceStudio/issues/533)) — so a
+  profile saved as, say, Persian still reaches Kokoro and is still refused. The
+  error names the profile as the source in that case
+  ([#2156](https://github.com/debpalash/VoiceStudio/issues/2156)); change the
+  profile's language, or pick a supported one explicitly for the render.
 
 ## Platform notes
 
@@ -79,6 +86,10 @@ See also: [benchmarks.md](../benchmarks.md),
 Consecutive chunks with the same native sample rate are resampled together to
 preserve filter context at chunk boundaries; rate changes start a new group.
 
+Profile language refusals are terminal request errors on both local and remote
+rendering, including streaming. Electron and web show localized guidance that
+Auto inherits the profile language; neither silently retries the same refusal.
+
 Kokoro language errors list every language in the installed model’s table.
 “British English” and `en-gb` both select its British English voice pipeline.
 Display names from newer installed Kokoro tables are accepted too, so a language

electron/src/renderer/src/i18n/locales/ar.json

@@ -2530,6 +2530,7 @@
     "recorder_unsupported": "لا يستطيع هذا النظام ترميز صوت الميكروفون."
   },
   "tts_errors": {
+    "profile_language_rejected": "يستخدم الوضع التلقائي لغة ملف الصوت ({{language}})، التي لا يدعمها هذا المحرك. غيّر لغة الملف أو اختر لغة مدعومة أو بدّل المحرك.",
     "generation_in_progress": "هناك عملية توليد قيد التشغيل بالفعل — انتظر حتى تنتهي قبل بدء عملية أخرى.",
     "error_prefix": "خطأ: {{message}}",
     "ignored_duplicate": "تم التجاهل (تم تعيين الفئة بالفعل): {{items}}",

electron/src/renderer/src/i18n/locales/de.json

@@ -2522,6 +2522,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Automatisch verwendet die Sprache des Stimmprofils ({{language}}), die diese Engine nicht unterstützt. Ändere die Profilsprache, wähle eine unterstützte Sprache oder wechsle die Engine.",
     "generation_in_progress": "Eine Generierung läuft bereits – warte, bis sie abgeschlossen ist, bevor du eine weitere startest.",
     "error_prefix": "Fehler: {{message}}",
     "ignored_duplicate": "Ignoriert (Kategorie bereits festgelegt): {{items}}",

electron/src/renderer/src/i18n/locales/en.json

@@ -292,6 +292,7 @@
     "recorder_unsupported": "This system cannot encode microphone audio."
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto uses the voice profile’s language ({{language}}), which this engine does not support. Change the profile language, choose a supported language, or switch engines.",
     "enter_text": "Enter some text first.",
     "upload_or_select": "Upload a reference clip or pick a saved voice.",
     "trim_hint": "The clip is {{duration}}s — trim to ≤{{max}}s for best cloning.",

electron/src/renderer/src/i18n/locales/es.json

@@ -2524,6 +2524,7 @@
     "channels_mono": "Mono"
   },
   "tts_errors": {
+    "profile_language_rejected": "Automático usa el idioma del perfil de voz ({{language}}), que este motor no admite. Cambia el idioma del perfil, elige uno compatible o cambia de motor.",
     "generation_in_progress": "Ya hay una generación en curso; espera a que termine antes de iniciar otra.",
     "ignored_duplicate": "Ignorado (categoría ya establecida): {{items}}",
     "ignored_conflict": "Se ignoró {{items}} — un dialecto chino y un acento inglés no se pueden combinar.",

electron/src/renderer/src/i18n/locales/fr.json

@@ -2524,6 +2524,7 @@
     "microphone_number": "Microphone {{number}}"
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto utilise la langue du profil vocal ({{language}}), non prise en charge par ce moteur. Modifiez la langue du profil, choisissez une langue compatible ou changez de moteur.",
     "generation_in_progress": "Une génération est déjà en cours — attendez sa fin avant d’en lancer une autre.",
     "error_prefix": "Erreur : {{message}}",
     "ignored_duplicate": "Ignoré (catégorie déjà définie) : {{items}}",

electron/src/renderer/src/i18n/locales/hi.json

@@ -2522,6 +2522,7 @@
     "recorder_unsupported": "यह सिस्टम माइक्रोफ़ोन ऑडियो एन्कोड नहीं कर सकता।"
   },
   "tts_errors": {
+    "profile_language_rejected": "ऑटो वॉइस प्रोफ़ाइल की भाषा ({{language}}) का उपयोग करता है, जिसे यह इंजन समर्थन नहीं करता। प्रोफ़ाइल की भाषा बदलें, समर्थित भाषा चुनें या इंजन बदलें।",
     "generation_in_progress": "एक जनरेशन पहले से चल रहा है — दूसरा शुरू करने से पहले उसके पूरा होने की प्रतीक्षा करें।",
     "error_prefix": "त्रुटि: {{message}}",
     "ignored_duplicate": "अनदेखा (श्रेणी पहले से ही सेट): {{items}}",

electron/src/renderer/src/i18n/locales/id.json

@@ -2522,6 +2522,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Otomatis menggunakan bahasa profil suara ({{language}}), yang tidak didukung mesin ini. Ubah bahasa profil, pilih bahasa yang didukung, atau ganti mesin.",
     "generation_in_progress": "Pembuatan sedang berjalan — tunggu hingga selesai sebelum memulai yang lain.",
     "error_prefix": "Kesalahan: {{message}}",
     "ignored_duplicate": "Diabaikan (kategori sudah ditetapkan): {{items}}",

electron/src/renderer/src/i18n/locales/it.json

@@ -2524,6 +2524,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto usa la lingua del profilo vocale ({{language}}), non supportata da questo motore. Modifica la lingua del profilo, scegli una lingua supportata o cambia motore.",
     "generation_in_progress": "È già in corso una generazione: attendi che termini prima di avviarne un’altra.",
     "error_prefix": "Errore: {{message}}",
     "ignored_duplicate": "Ignorato (categoria già impostata): {{items}}",

electron/src/renderer/src/i18n/locales/ja.json

@@ -2522,6 +2522,7 @@
     "recorder_unsupported": "このシステムではマイク音声をエンコードできません。"
   },
   "tts_errors": {
+    "profile_language_rejected": "自動では音声プロファイルの言語（{{language}}）が使われますが、このエンジンは対応していません。プロファイルの言語を変更するか、対応言語または別のエンジンを選択してください。",
     "generation_in_progress": "生成がすでに実行中です。完了してから次の生成を開始してください。",
     "error_prefix": "エラー: {{message}}",
     "ignored_duplicate": "無視 (カテゴリはすでに設定されています): {{items}}",

electron/src/renderer/src/i18n/locales/ko.json

@@ -2522,6 +2522,7 @@
     "recorder_unsupported": "이 시스템에서는 마이크 오디오를 인코딩할 수 없습니다."
   },
   "tts_errors": {
+    "profile_language_rejected": "자동은 이 엔진이 지원하지 않는 음성 프로필의 언어({{language}})를 사용합니다. 프로필 언어를 변경하거나 지원되는 언어 또는 다른 엔진을 선택하세요.",
     "generation_in_progress": "이미 생성 작업이 실행 중입니다. 완료된 후 새 작업을 시작하세요.",
     "error_prefix": "오류: {{message}}",
     "ignored_duplicate": "무시됨(카테고리가 이미 설정됨): {{items}}",

electron/src/renderer/src/i18n/locales/nl.json

@@ -2522,6 +2522,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Automatisch gebruikt de taal van het stemprofiel ({{language}}), die deze engine niet ondersteunt. Wijzig de profieltaal, kies een ondersteunde taal of wissel van engine.",
     "generation_in_progress": "Er wordt al audio gegenereerd — wacht tot dit klaar is voordat je opnieuw begint.",
     "error_prefix": "Fout: {{message}}",
     "ignored_duplicate": "Genegeerd (categorie al ingesteld): {{items}}",

electron/src/renderer/src/i18n/locales/pl.json

@@ -2526,6 +2526,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Tryb automatyczny używa języka profilu głosu ({{language}}), którego ten silnik nie obsługuje. Zmień język profilu, wybierz obsługiwany język lub zmień silnik.",
     "generation_in_progress": "Generowanie już trwa — poczekaj na jego zakończenie przed rozpoczęciem kolejnego.",
     "error_prefix": "Błąd: {{message}}",
     "ignored_duplicate": "Ignorowane (kategoria już ustawiona): {{items}}",

electron/src/renderer/src/i18n/locales/pt.json

@@ -2524,6 +2524,7 @@
     "channels_mono": "Mono"
   },
   "tts_errors": {
+    "profile_language_rejected": "Automático usa o idioma do perfil de voz ({{language}}), não suportado por este motor. Altere o idioma do perfil, escolha um idioma compatível ou mude de motor.",
     "generation_in_progress": "Já existe uma geração em andamento — aguarde a conclusão antes de iniciar outra.",
     "error_prefix": "Erro: {{message}}",
     "ignored_duplicate": "Ignorado (categoria já definida): {{items}}",

electron/src/renderer/src/i18n/locales/ru.json

@@ -2526,6 +2526,7 @@
     "recorder_unsupported": "Эта система не может кодировать звук с микрофона."
   },
   "tts_errors": {
+    "profile_language_rejected": "Авто использует язык голосового профиля ({{language}}), который этот движок не поддерживает. Измените язык профиля, выберите поддерживаемый язык или другой движок.",
     "generation_in_progress": "Генерация уже выполняется — дождитесь её завершения, прежде чем запускать следующую.",
     "error_prefix": "Ошибка: {{message}}",
     "ignored_duplicate": "Игнорируется (категория уже установлена): {{items}}",

electron/src/renderer/src/i18n/locales/sv.json

@@ -2522,6 +2522,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto använder röstprofilens språk ({{language}}), som denna motor inte stöder. Ändra profilens språk, välj ett språk som stöds eller byt motor.",
     "generation_in_progress": "En generering pågår redan – vänta tills den är klar innan du startar en ny.",
     "error_prefix": "Fel: {{message}}",
     "ignored_duplicate": "Ignorerad (kategori redan inställd): {{items}}",

electron/src/renderer/src/i18n/locales/th.json

@@ -2522,6 +2522,7 @@
     "recorder_unsupported": "ระบบนี้ไม่สามารถเข้ารหัสเสียงจากไมโครโฟนได้"
   },
   "tts_errors": {
+    "profile_language_rejected": "อัตโนมัติใช้ภาษาของโปรไฟล์เสียง ({{language}}) ซึ่งเอนจินนี้ไม่รองรับ เปลี่ยนภาษาโปรไฟล์ เลือกภาษาที่รองรับ หรือเปลี่ยนเอนจิน",
     "generation_in_progress": "มีการสร้างเสียงกำลังทำงานอยู่ — รอให้เสร็จก่อนเริ่มงานใหม่",
     "error_prefix": "ข้อผิดพลาด: {{message}}",
     "ignored_duplicate": "ละเว้น (หมวดหมู่ที่ตั้งไว้แล้ว): {{items}}",

electron/src/renderer/src/i18n/locales/tr.json

@@ -2522,6 +2522,7 @@
     "channels_stereo": "Stereo"
   },
   "tts_errors": {
+    "profile_language_rejected": "Otomatik, bu motorun desteklemediği ses profili dilini ({{language}}) kullanır. Profil dilini değiştirin, desteklenen bir dil seçin veya motoru değiştirin.",
     "generation_in_progress": "Bir oluşturma işlemi zaten çalışıyor — yenisini başlatmadan önce bitmesini bekleyin.",
     "error_prefix": "Hata: {{message}}",
     "ignored_duplicate": "Yoksayıldı (kategori zaten ayarlandı): {{items}}",

electron/src/renderer/src/i18n/locales/uk.json

@@ -2526,6 +2526,7 @@
     "recorder_unsupported": "Ця система не може кодувати звук із мікрофона."
   },
   "tts_errors": {
+    "profile_language_rejected": "Авто використовує мову голосового профілю ({{language}}), яку цей рушій не підтримує. Змініть мову профілю, виберіть підтримувану мову або інший рушій.",
     "generation_in_progress": "Генерація вже виконується — дочекайтеся її завершення, перш ніж запускати наступну.",
     "error_prefix": "Помилка: {{message}}",
     "ignored_duplicate": "Проігноровано (категорію вже встановлено): {{items}}",

electron/src/renderer/src/i18n/locales/vi.json

@@ -2522,6 +2522,7 @@
     "recorder_unsupported": "Hệ thống này không thể mã hóa âm thanh từ micrô."
   },
   "tts_errors": {
+    "profile_language_rejected": "Tự động sử dụng ngôn ngữ của hồ sơ giọng nói ({{language}}), nhưng bộ máy này không hỗ trợ. Đổi ngôn ngữ hồ sơ, chọn ngôn ngữ được hỗ trợ hoặc đổi bộ máy.",
     "generation_in_progress": "Một tác vụ tạo âm thanh đang chạy — hãy đợi hoàn tất trước khi bắt đầu tác vụ khác.",
     "error_prefix": "Lỗi: {{message}}",
     "ignored_duplicate": "Đã bỏ qua (danh mục đã được đặt): {{items}}",

electron/src/renderer/src/i18n/locales/zh-CN.json

@@ -2526,6 +2526,7 @@
     "recorder_unsupported": "此系统无法编码麦克风音频。"
   },
   "tts_errors": {
+    "profile_language_rejected": "自动模式使用声音档案的语言（{{language}}），但此引擎不支持该语言。请修改档案语言、选择支持的语言或更换引擎。",
     "generation_in_progress": "已有生成任务正在运行，请等待其完成后再启动新任务。",
     "error_prefix": "错误：{{message}}",
     "ignored_duplicate": "忽略（类别已设置）：{{items}}",

electron/src/renderer/src/i18n/locales/zh-TW.json

@@ -2522,6 +2522,7 @@
     "recorder_unsupported": "此系統無法編碼麥克風音訊。"
   },
   "tts_errors": {
+    "profile_language_rejected": "自動模式使用聲音設定檔的語言（{{language}}），但此引擎不支援該語言。請修改設定檔語言、選擇支援的語言或更換引擎。",
     "generation_in_progress": "已有產生工作正在執行，請等待完成後再啟動新工作。",
     "error_prefix": "錯誤：{{message}}",
     "ignored_duplicate": "忽略（類別已設定）：{{items}}",

electron/src/renderer/src/lib/api/client.test.ts

@@ -169,3 +169,23 @@ it('uses a structured error message without losing recovery metadata', async ()
   expect(error.message).toBe(detail.message);
   expect(error.payload?.detail).toEqual(detail);
 });
+
+it('localizes structured profile language failures', async () => {
+  const translate = vi.spyOn(i18next, 't').mockReturnValue('Localized profile guidance');
+  try {
+    const detail = {
+      code: 'profile_language_rejected',
+      language: 'Persian',
+      message: 'English fallback',
+    };
+    const error = await errorFromResponse(
+      new Response(JSON.stringify({ detail }), { status: 400 }),
+    );
+    expect(error.detail).toBe('Localized profile guidance');
+    expect(translate).toHaveBeenCalledWith('tts_errors.profile_language_rejected', {
+      language: 'Persian',
+    });
+  } finally {
+    translate.mockRestore();
+  }
+});

electron/src/renderer/src/lib/api/client.ts

@@ -1,3 +1,4 @@
+import { languageRejectionMessage } from '../../../../../../frontend/src/utils/languageRejection.ts';
 /**
  * Same-origin API client. The renderer never talks to 127.0.0.1:<port>
  * directly (CORS); `/api/*` is proxied by the dev server / the app:// protocol
@@ -44,6 +45,8 @@ export function describeError(err: unknown): string {
 }
 
 function detailToString(detail: unknown): string {
+  const localized = languageRejectionMessage(detail, tr);
+  if (localized) return localized;
   if (
     detail &&
     typeof detail === 'object' &&

electron/src/renderer/src/lib/api/generate.test.ts

@@ -1,8 +1,11 @@
+import i18n from 'i18next';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 import {
   CLONE_MAX_SECONDS,
   REF_HARD_MAX_SECONDS,
   generateClone,
+  generateCloneStreaming,
+  shouldFallbackToClassic,
   parseGenerateHeaders,
   sanitizeInstruct,
   toGenerateForm,
@@ -277,3 +280,31 @@ describe('generateClone', () => {
     await assertion;
   });
 });
+
+it('localizes streamed profile language refusals and prevents classic fallback', async () => {
+  const translate = vi.spyOn(i18n, 't').mockReturnValue('Localized profile guidance');
+  try {
+    vi.stubGlobal(
+      'fetch',
+      vi.fn(
+        async () =>
+          new Response(
+            JSON.stringify({
+              type: 'error',
+              code: 'profile_language_rejected',
+              language: 'Persian',
+              detail: 'English fallback',
+              retryable: false,
+              terminal: true,
+            }) + '\n',
+            { headers: { 'content-type': 'application/x-ndjson' } },
+          ),
+      ),
+    );
+    const error = await generateCloneStreaming(BASE_INPUT).catch((e) => e);
+    expect(error.message).toBe('Localized profile guidance');
+    expect(shouldFallbackToClassic(error)).toBe(false);
+  } finally {
+    translate.mockRestore();
+  }
+});

electron/src/renderer/src/lib/api/generate.ts

@@ -1,3 +1,5 @@
+import i18next from 'i18next';
+import { languageRejectionMessage } from '../../../../../../frontend/src/utils/languageRejection.ts';
 import { ApiError, apiFetch, isAbortError } from './client';
 import type { CloneGenerateInput, GenerateResult } from './types';
 import { beginAppActivity } from '@/lib/app-activity';
@@ -255,6 +257,9 @@ interface StreamEvent {
   count?: number;
   text?: string[];
   detail?: string;
+  code?: string;
+  language?: string;
+  terminal?: boolean;
   retryable?: boolean;
   percent?: number;
 }
@@ -300,12 +305,15 @@ export async function generateCloneStreaming(
       } else if (event.type === 'done') {
         meta = event;
       } else if (event.type === 'error') {
-        const message = event.detail || 'TTS stream reported an error';
-        const terminal = [
-          '[clone_ref_unusable]',
-          '[clone_ref_too_long]',
-          '[clone_ref_no_speech]',
-        ].some((marker) => message.includes(marker));
+        const message =
+          languageRejectionMessage(event, i18next.t) ||
+          event.detail ||
+          'TTS stream reported an error';
+        const terminal =
+          event.terminal === true ||
+          ['[clone_ref_unusable]', '[clone_ref_too_long]', '[clone_ref_no_speech]'].some((marker) =>
+            message.includes(marker),
+          );
         throw new StreamingPreviewError(message, { retryable: event.retryable, terminal });
       }
     };

electron/tsconfig.web.json

@@ -27,6 +27,7 @@
     "src/preload/index.d.ts",
     "src/shared/**/*",
     "src/renderer/env.d.ts",
+    "../frontend/src/utils/languageRejection.ts",
     "../frontend/src/utils/coalescedJsonStorage.ts",
     "../frontend/src/utils/indexedDbLongformStore.ts",
     "../frontend/src/utils/cookieExport.ts",

frontend/src/api/client.ts

@@ -1,3 +1,4 @@
+import { languageRejectionMessage } from '../utils/languageRejection.ts';
 import i18n from 'i18next';
 import { abortableDelay } from '../utils/abortableDelay.ts';
 // Backend base URL.
@@ -593,7 +594,8 @@ export async function apiFetch(path: string, opts: ApiFetchOptions = {}): Promis
       // human-readable `message` — use it for the Error message instead of
       // letting the object stringify to "[object Object]".
       const msg =
-        detail &&
+        languageRejectionMessage(detail, i18n.t) ||
+        (detail &&
         typeof detail === 'object' &&
         'code' in detail &&
         detail.code === 'argos_runtime_unavailable'
@@ -602,7 +604,7 @@ export async function apiFetch(path: string, opts: ApiFetchOptions = {}): Promis
             })
           : typeof detail === 'string'
             ? detail
-            : ((detail as { message?: string })?.message ?? JSON.stringify(detail));
+            : ((detail as { message?: string })?.message ?? JSON.stringify(detail)));
       // The backend names the exception type in `error_class` on its 500s.
       // Lifting it here is what lets the bug report say which failure it was.
       const errorClass =

frontend/src/i18n/locales/ar.json

@@ -2219,6 +2219,7 @@
     "session_expired": "انتهت صلاحية جلسة الدبلجة هذه أو تم تنظيفها — أعد تحميل الفيديو لبدء مقطع جديد."
   },
   "tts_errors": {
+    "profile_language_rejected": "يستخدم الوضع التلقائي لغة ملف الصوت ({{language}})، التي لا يدعمها هذا المحرك. غيّر لغة الملف أو اختر لغة مدعومة أو بدّل المحرك.",
     "enter_text": "الرجاء إدخال النص",
     "upload_or_select": "قم بتحميل ملف صوتي أو حدد ملفًا صوتيًا",
     "trim_hint": "الصوت هو {{duration}}s — قم بقصه إلى ≥{{max}}s للحصول على أفضل استنساخ",

frontend/src/i18n/locales/de.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Diese Dub-Sitzung ist abgelaufen oder wurde bereinigt. Laden Sie Ihr Video erneut hoch, um eine neue zu starten."
   },
   "tts_errors": {
+    "profile_language_rejected": "Automatisch verwendet die Sprache des Stimmprofils ({{language}}), die diese Engine nicht unterstützt. Ändere die Profilsprache, wähle eine unterstützte Sprache oder wechsle die Engine.",
     "enter_text": "Bitte geben Sie Text ein",
     "upload_or_select": "Laden Sie ein Audio hoch oder wählen Sie ein Sprachprofil aus",
     "trim_hint": "Audio ist {{duration}}s – für bestes Klonen auf ≤{{max}}s kürzen",

frontend/src/i18n/locales/en.json

@@ -2890,6 +2890,7 @@
     "upgrading_preview": "Upgrading {{count}} preview-quality segment(s) to full quality…"
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto uses the voice profile’s language ({{language}}), which this engine does not support. Change the profile language, choose a supported language, or switch engines.",
     "enter_text": "Please enter text",
     "upload_or_select": "Upload an audio or select a voice profile",
     "trim_hint": "Audio is {{duration}}s — trim to ≤{{max}}s for best cloning",

frontend/src/i18n/locales/es.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Esta sesión de doblaje expiró o se limpió: vuelve a subir tu video para comenzar uno nuevo."
   },
   "tts_errors": {
+    "profile_language_rejected": "Automático usa el idioma del perfil de voz ({{language}}), que este motor no admite. Cambia el idioma del perfil, elige uno compatible o cambia de motor.",
     "enter_text": "Por favor ingresa texto",
     "upload_or_select": "Sube un audio o selecciona un perfil de voz",
     "trim_hint": "El audio es {{duration}}s; recórtelo a ≤{{max}}s para una mejor clonación.",

frontend/src/i18n/locales/fr.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Cette session de doublage a expiré ou a été nettoyée : téléchargez à nouveau votre vidéo pour en démarrer une nouvelle."
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto utilise la langue du profil vocal ({{language}}), non prise en charge par ce moteur. Modifiez la langue du profil, choisissez une langue compatible ou changez de moteur.",
     "enter_text": "Veuillez saisir du texte",
     "upload_or_select": "Téléchargez un audio ou sélectionnez un profil vocal",
     "trim_hint": "L'audio est de {{duration}}s — coupez à ≤{{max}}s pour un meilleur clonage",

frontend/src/i18n/locales/hi.json

@@ -2219,6 +2219,7 @@
     "session_expired": "यह डब सत्र समाप्त हो गया है या साफ़ कर दिया गया है - नया शुरू करने के लिए अपना वीडियो पुनः अपलोड करें।"
   },
   "tts_errors": {
+    "profile_language_rejected": "ऑटो वॉइस प्रोफ़ाइल की भाषा ({{language}}) का उपयोग करता है, जिसे यह इंजन समर्थन नहीं करता। प्रोफ़ाइल की भाषा बदलें, समर्थित भाषा चुनें या इंजन बदलें।",
     "enter_text": "कृपया पाठ दर्ज करें",
     "upload_or_select": "एक ऑडियो अपलोड करें या एक वॉयस प्रोफ़ाइल चुनें",
     "trim_hint": "ऑडियो {{duration}}s है - सर्वोत्तम क्लोनिंग के लिए ≤{{max}}s तक ट्रिम करें",

frontend/src/i18n/locales/id.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Sesi sulih suara ini telah habis masa berlakunya atau telah dibersihkan — unggah ulang video Anda untuk memulai yang baru."
   },
   "tts_errors": {
+    "profile_language_rejected": "Otomatis menggunakan bahasa profil suara ({{language}}), yang tidak didukung mesin ini. Ubah bahasa profil, pilih bahasa yang didukung, atau ganti mesin.",
     "enter_text": "Silakan masukkan teks",
     "upload_or_select": "Unggah audio atau pilih profil suara",
     "trim_hint": "Audio adalah {{duration}}s — potong ke ≤{{max}}s untuk kloning terbaik",

frontend/src/i18n/locales/it.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Questa sessione di doppiaggio è scaduta o è stata ripulita: ricarica il tuo video per avviarne uno nuovo."
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto usa la lingua del profilo vocale ({{language}}), non supportata da questo motore. Modifica la lingua del profilo, scegli una lingua supportata o cambia motore.",
     "enter_text": "Inserisci il testo",
     "upload_or_select": "Carica un audio o seleziona un profilo vocale",
     "trim_hint": "L'audio è {{duration}}s: taglia a ≤{{max}}s per una migliore clonazione",

frontend/src/i18n/locales/ja.json

@@ -2219,6 +2219,7 @@
     "session_expired": "このダビング セッションは期限切れかクリーンアップされました。新しいビデオを開始するにはビデオを再アップロードしてください。"
   },
   "tts_errors": {
+    "profile_language_rejected": "自動では音声プロファイルの言語（{{language}}）が使われますが、このエンジンは対応していません。プロファイルの言語を変更するか、対応言語または別のエンジンを選択してください。",
     "enter_text": "テキストを入力してください",
     "upload_or_select": "音声をアップロードするか、音声プロファイルを選択してください",
     "trim_hint": "オーディオは {{duration}}s — 最適なクローン作成のために ≤{{max}}s にトリミングします",

frontend/src/i18n/locales/ko.json

@@ -2600,6 +2600,7 @@
     "session_expired": "이 더빙 세션이 만료되었거나 정리되었습니다. 새 동영상을 시작하려면 동영상을 다시 업로드하세요."
   },
   "tts_errors": {
+    "profile_language_rejected": "자동은 이 엔진이 지원하지 않는 음성 프로필의 언어({{language}})를 사용합니다. 프로필 언어를 변경하거나 지원되는 언어 또는 다른 엔진을 선택하세요.",
     "enter_text": "텍스트를 입력해주세요",
     "upload_or_select": "오디오 업로드 또는 음성 프로필 선택",
     "trim_hint": "오디오는 {{duration}}s입니다. 최상의 복제를 위해 ≤{{max}}s로 조정하세요.",

frontend/src/i18n/locales/nl.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Deze kopieersessie is verlopen of opgeschoond. Upload je video opnieuw om een nieuwe te starten."
   },
   "tts_errors": {
+    "profile_language_rejected": "Automatisch gebruikt de taal van het stemprofiel ({{language}}), die deze engine niet ondersteunt. Wijzig de profieltaal, kies een ondersteunde taal of wissel van engine.",
     "enter_text": "Voer tekst in",
     "upload_or_select": "Upload een audio of selecteer een stemprofiel",
     "trim_hint": "Audio is {{duration}}s — trim tot ≤{{max}}s voor de beste kloonfunctie",

frontend/src/i18n/locales/pl.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Ta sesja dubowania wygasła lub została wyczyszczona — prześlij film ponownie, aby rozpocząć nową."
   },
   "tts_errors": {
+    "profile_language_rejected": "Tryb automatyczny używa języka profilu głosu ({{language}}), którego ten silnik nie obsługuje. Zmień język profilu, wybierz obsługiwany język lub zmień silnik.",
     "enter_text": "Proszę wpisać tekst",
     "upload_or_select": "Prześlij plik audio lub wybierz profil głosowy",
     "trim_hint": "Dźwięk wynosi {{duration}}s — przytnij do ≤{{max}}s, aby uzyskać najlepsze klonowanie",

frontend/src/i18n/locales/pt.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Esta sessão de dublagem expirou ou foi limpa. Reenvie seu vídeo para iniciar uma nova."
   },
   "tts_errors": {
+    "profile_language_rejected": "Automático usa o idioma do perfil de voz ({{language}}), não suportado por este motor. Altere o idioma do perfil, escolha um idioma compatível ou mude de motor.",
     "enter_text": "Por favor insira o texto",
     "upload_or_select": "Carregue um áudio ou selecione um perfil de voz",
     "trim_hint": "O áudio é {{duration}}s – ajuste para ≤{{max}}s para melhor clonagem",

frontend/src/i18n/locales/ru.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Срок действия сеанса дублирования истек или он был удален — загрузите видео повторно, чтобы начать новое."
   },
   "tts_errors": {
+    "profile_language_rejected": "Авто использует язык голосового профиля ({{language}}), который этот движок не поддерживает. Измените язык профиля, выберите поддерживаемый язык или другой движок.",
     "enter_text": "Пожалуйста, введите текст",
     "upload_or_select": "Загрузите аудио или выберите голосовой профиль",
     "trim_hint": "Звук составляет {{duration}}s — обрезайте до ≤{{max}}s для лучшего клонирования",

frontend/src/i18n/locales/sv.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Den här dubbsessionen löpte ut eller rensades upp – ladda upp din video igen för att starta en ny."
   },
   "tts_errors": {
+    "profile_language_rejected": "Auto använder röstprofilens språk ({{language}}), som denna motor inte stöder. Ändra profilens språk, välj ett språk som stöds eller byt motor.",
     "enter_text": "Vänligen ange text",
     "upload_or_select": "Ladda upp ett ljud eller välj en röstprofil",
     "trim_hint": "Ljudet är {{duration}}s — trimma till ≤{{max}}s för bästa kloning",

frontend/src/i18n/locales/th.json

@@ -2219,6 +2219,7 @@
     "session_expired": "เซสชั่นพากย์นี้หมดอายุหรือถูกล้างออกไปแล้ว — อัปโหลดวิดีโอของคุณอีกครั้งเพื่อเริ่มวิดีโอใหม่"
   },
   "tts_errors": {
+    "profile_language_rejected": "อัตโนมัติใช้ภาษาของโปรไฟล์เสียง ({{language}}) ซึ่งเอนจินนี้ไม่รองรับ เปลี่ยนภาษาโปรไฟล์ เลือกภาษาที่รองรับ หรือเปลี่ยนเอนจิน",
     "enter_text": "กรุณากรอกข้อความ",
     "upload_or_select": "อัปโหลดเสียงหรือเลือกโปรไฟล์เสียง",
     "trim_hint": "เสียงคือ {{duration}}s — ตัดเป็น ≤{{max}}s เพื่อการโคลนที่ดีที่สุด",

frontend/src/i18n/locales/tr.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Bu dub oturumunun süresi doldu veya temizlendi. Yeni bir video başlatmak için videonuzu yeniden yükleyin."
   },
   "tts_errors": {
+    "profile_language_rejected": "Otomatik, bu motorun desteklemediği ses profili dilini ({{language}}) kullanır. Profil dilini değiştirin, desteklenen bir dil seçin veya motoru değiştirin.",
     "enter_text": "Lütfen metni girin",
     "upload_or_select": "Bir ses yükleyin veya bir ses profili seçin",
     "trim_hint": "Ses {{duration}}s — en iyi klonlama için ≤{{max}}s'ye kırpın",

frontend/src/i18n/locales/uk.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Цей сеанс дубляжу закінчився або його було очищено — повторно завантажте відео, щоб почати нове."
   },
   "tts_errors": {
+    "profile_language_rejected": "Авто використовує мову голосового профілю ({{language}}), яку цей рушій не підтримує. Змініть мову профілю, виберіть підтримувану мову або інший рушій.",
     "enter_text": "Будь ласка, введіть текст",
     "upload_or_select": "Завантажте аудіо або виберіть голосовий профіль",
     "trim_hint": "Аудіо {{duration}}s — обріжте до ≤{{max}}s для найкращого клонування",

frontend/src/i18n/locales/vi.json

@@ -2219,6 +2219,7 @@
     "session_expired": "Phiên lồng tiếng này đã hết hạn hoặc đã bị xóa - hãy tải lại video của bạn lên để bắt đầu một video mới."
   },
   "tts_errors": {
+    "profile_language_rejected": "Tự động sử dụng ngôn ngữ của hồ sơ giọng nói ({{language}}), nhưng bộ máy này không hỗ trợ. Đổi ngôn ngữ hồ sơ, chọn ngôn ngữ được hỗ trợ hoặc đổi bộ máy.",
     "enter_text": "Vui lòng nhập văn bản",
     "upload_or_select": "Tải lên âm thanh hoặc chọn cấu hình giọng nói",
     "trim_hint": "Âm thanh là {{duration}}s — cắt thành ≤{{max}}s để sao chép tốt nhất",

frontend/src/i18n/locales/zh-CN.json

@@ -2605,6 +2605,7 @@
     "session_expired": "此配音会话已过期或已清理——请重新上传视频以开始新的会话。"
   },
   "tts_errors": {
+    "profile_language_rejected": "自动模式使用声音档案的语言（{{language}}），但此引擎不支持该语言。请修改档案语言、选择支持的语言或更换引擎。",
     "enter_text": "请输入文字",
     "upload_or_select": "上传音频或选择语音配置文件",
     "trim_hint": "音频为 {{duration}}s — 修剪至 ≤{{max}}s 以获得最佳克隆效果",

frontend/src/i18n/locales/zh-TW.json

@@ -2219,6 +2219,7 @@
     "session_expired": "此配音會話已過期或已清理 - 重新上傳您的影片以開始新的影片。"
   },
   "tts_errors": {
+    "profile_language_rejected": "自動模式使用聲音設定檔的語言（{{language}}），但此引擎不支援該語言。請修改設定檔語言、選擇支援的語言或更換引擎。",
     "enter_text": "請輸入文字",
     "upload_or_select": "上傳音訊或選擇語音設定文件",
     "trim_hint": "音訊為 {{duration}}s — 修剪至 ≤{{max}}s 以獲得最佳克隆效果",

frontend/src/test/streamingTts.test.js

@@ -1,3 +1,4 @@
+import i18n from 'i18next';
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 
 // Streaming TTS preview (feat: streaming-tts-preview): the NDJSON client must
@@ -380,6 +381,32 @@ describe('streamGenerateSpeech', () => {
     expect(plain.retryable).toBe(false);
   });
 
+  it('localizes a terminal profile language refusal without retrying', async () => {
+    const translate = vi.spyOn(i18n, 't').mockReturnValue('Localized profile guidance');
+    try {
+      apiFetch.mockResolvedValue(
+        ndjsonResponse([
+          {
+            type: 'error',
+            code: 'profile_language_rejected',
+            language: 'Persian',
+            detail: 'English fallback',
+            retryable: false,
+            terminal: true,
+          },
+        ]),
+      );
+      const error = await streamGenerateSpeech(new FormData(), {}).catch((e) => e);
+      expect(error.message).toBe('Localized profile guidance');
+      expect(shouldFallbackToClassic(error)).toBe(false);
+      expect(translate).toHaveBeenCalledWith('tts_errors.profile_language_rejected', {
+        language: 'Persian',
+      });
+    } finally {
+      translate.mockRestore();
+    }
+  });
+
   it('marks actionable clone-reference errors terminal to prevent a classic retry', async () => {
     apiFetch.mockResolvedValue(
       ndjsonResponse([

frontend/src/utils/languageRejection.ts

@@ -0,0 +1,11 @@
+/** Localize only the known structured failure, never a server-supplied key. */
+export function languageRejectionMessage(
+  value: unknown,
+  translate: (key: string, options: { language: string }) => string,
+): string | undefined {
+  if (!value || typeof value !== 'object') return undefined;
+  const failure = value as { code?: unknown; language?: unknown };
+  if (failure.code !== 'profile_language_rejected' || typeof failure.language !== 'string')
+    return undefined;
+  return translate('tts_errors.profile_language_rejected', { language: failure.language });
+}

frontend/src/utils/streamingTts.js

@@ -1,3 +1,5 @@
+import i18n from 'i18next';
+import { languageRejectionMessage } from './languageRejection.ts';
 /**
  * streamingTts.js — streaming TTS preview (feat: streaming-tts-preview).
  *
@@ -399,12 +401,13 @@ async function _streamGenerateSpeech(
       } else if (ev.type === 'done') {
         meta = ev;
       } else if (ev.type === 'error') {
-        const detail = ev.detail || 'TTS stream reported an error';
-        const terminal = [
-          '[clone_ref_unusable]',
-          '[clone_ref_too_long]',
-          '[clone_ref_no_speech]',
-        ].some((marker) => detail.includes(marker));
+        const detail =
+          languageRejectionMessage(ev, i18n.t) || ev.detail || 'TTS stream reported an error';
+        const terminal =
+          ev.terminal === true ||
+          ['[clone_ref_unusable]', '[clone_ref_too_long]', '[clone_ref_no_speech]'].some((marker) =>
+            detail.includes(marker),
+          );
         throw new StreamingPreviewError(detail, {
           retryable: ev.retryable === true,
           retryAfter: ev.retry_after ?? null,

tests/test_profile_language_rejection_2156.py

@@ -0,0 +1,458 @@
+"""#2156: a language the user never picked must not be blamed on the picker.
+
+The reporter was on mlx-audio (Kokoro) with the language picker on "Auto" and
+got:
+
+    400 Bad Request: mlx-audio's Kokoro model (mlx-community/Kokoro-82M-bf16)
+    doesn't support language='Persian'. … Pick one of those, leave language as
+    'Auto', or switch to a multilingual engine …
+
+They had left it on Auto. The UI omits `language` entirely while its picker
+reads "Auto" (`frontend/src/hooks/useProfiles.js`: `if (reqLang && reqLang !==
+'Auto') formData.append(...)`), and #533 fills that gap from the selected voice
+profile. So "Auto" is precisely how 'Persian' got there — the one remedy the
+message leads with is the state the user was already in, and nothing in it
+points at the voice profile that actually supplied the language.
+
+This completes #1257's line of work rather than reopening it: that issue chose
+to name the engine and the way out instead of maintaining per-model language
+maps ("a brittle map that goes stale on each engine update"). Same principle
+here — say where the language came from, don't enumerate languages.
+"""
+import importlib
+import os
+import uuid
+
+import pytest
+import torch
+
+os.environ.setdefault("OMNIVOICE_MODEL", "test")
+os.environ.setdefault("OMNIVOICE_DISABLE_FILE_LOG", "1")
+
+def _gen_mod():
+    """Imported lazily so the end-to-end tests below still run (and fail on
+    their assertions, not on a missing symbol) against a tree without the fix."""
+    return importlib.import_module("api.routers.generation")
+
+
+# The real wording from services/tts_backend.py::resolve_kokoro_lang_code.
+KOKORO_REFUSAL = (
+    "mlx-audio's Kokoro model (mlx-community/Kokoro-82M-bf16) doesn't support "
+    "language='Persian'. Kokoro supports: Chinese, English, French, Hindi, "
+    "Italian, Japanese, Portuguese, Spanish. Pick one of those, leave language "
+    "as 'Auto', or switch to a multilingual engine (e.g. OmniVoice) for other "
+    "languages."
+)
+
+KOKORO_SUPPORTED = ("Chinese", "English", "French", "Hindi",
+                    "Italian", "Japanese", "Portuguese", "Spanish")
+
+
+def _tts_mod():
+    return importlib.import_module("services.tts_backend")
+
+
+def _make_refusing_engine(engine_id="fake-kokoro-2156"):
+    """An engine that refuses unknown languages the way Kokoro really does."""
+    class _FakeEngine(_tts_mod().TTSBackend):
+        id = engine_id
+        display_name = "Fake Kokoro (test)"
+        applies_own_mastering = False
+        gpu_compat = ("cpu",)
+        calls: list = []
+
+        @property
+        def sample_rate(self) -> int:
+            return 24000
+
+        @property
+        def supported_languages(self) -> list[str]:
+            return ["multi"]
+
+        @classmethod
+        def is_available(cls):
+            return True, "ready"
+
+        def generate(self, text, **kw) -> torch.Tensor:
+            type(self).calls.append((text, kw))
+            language = kw.get("language")
+            if language and language not in KOKORO_SUPPORTED:
+                raise ValueError(
+                    f"mlx-audio's Kokoro model (mlx-community/Kokoro-82M-bf16) "
+                    f"doesn't support language={language!r}. Kokoro supports: "
+                    f"{', '.join(KOKORO_SUPPORTED)}. Pick one of those, leave "
+                    f"language as 'Auto', or switch to a multilingual engine "
+                    f"(e.g. OmniVoice) for other languages."
+                )
+            return torch.zeros(1, 24000)
+
+    return _FakeEngine
+
+
+@pytest.fixture()
+def client():
+    from fastapi.testclient import TestClient
+    from main import app
+
+    return TestClient(app, client=("127.0.0.1", 50000))
+
+
+@pytest.fixture()
+def _init_db():
+    from core.db import init_db
+
+    init_db()
+
+
+def _profile(language):
+    from core.db import db_conn
+
+    pid = f"vp-{uuid.uuid4().hex[:8]}"
+    with db_conn() as conn:
+        conn.execute(
+            "INSERT INTO voice_profiles (id, name, language, kind, created_at) "
+            "VALUES (?,?,?,?,?)",
+            (pid, f"{language} Narrator", language, "clone", 0.0),
+        )
+    return pid
+
+
+def _drop(pid):
+    from core.db import db_conn
+
+    with db_conn() as conn:
+        conn.execute("DELETE FROM generation_history WHERE profile_id=?", (pid,))
+        conn.execute("DELETE FROM voice_profiles WHERE id=?", (pid,))
+
+
+@pytest.fixture()
+def persian_profile(_init_db):
+    pid = _profile("Persian")
+    yield pid
+    _drop(pid)
+
+
+@pytest.fixture()
+def english_profile(_init_db):
+    pid = _profile("English")
+    yield pid
+    _drop(pid)
+
+
+# ── the reported failure ────────────────────────────────────────────────────
+
+
+def test_a_profile_supplied_language_names_the_profile_not_the_picker(
+    client, monkeypatch, persian_profile
+):
+    fake = _make_refusing_engine()
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    fake.calls.clear()
+
+    # `language` omitted — exactly what the UI sends with the picker on "Auto".
+    res = client.post("/generate", data={
+        "text": "Salam", "profile_id": persian_profile, "engine": fake.id,
+    })
+
+    assert res.status_code == 400, res.text
+    detail = res.json()["detail"]
+    if isinstance(detail, dict):
+        assert detail["code"] == "profile_language_rejected"
+        assert detail["language"] == "Persian"
+        detail = detail["message"]
+    # Says where the language actually came from …
+    assert "voice profile" in detail.lower()
+    assert "Persian" in detail
+    # … and that Auto is not an escape from it, since Auto is what filled it in.
+    assert "does not override" in detail
+    # … and keeps the engine's own capability list, quoted once, not nested.
+    assert "Kokoro supports:" in detail
+    assert detail.count("Engine's own message:") == 1
+
+
+def test_the_profile_language_still_reached_the_engine(
+    client, monkeypatch, persian_profile
+):
+    """Guards the premise: this is a profile fill, not the user's choice."""
+    fake = _make_refusing_engine()
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    fake.calls.clear()
+
+    client.post("/generate", data={
+        "text": "Salam", "profile_id": persian_profile, "engine": fake.id,
+    })
+
+    assert [kw.get("language") for _t, kw in fake.calls] == ["Persian"]
+
+
+def test_an_explicitly_requested_language_is_not_blamed_on_the_profile(
+    client, monkeypatch, english_profile
+):
+    """The user really did pick it, so the profile wording would be a lie —
+    they get the engine's own message, unchanged."""
+    fake = _make_refusing_engine()
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    fake.calls.clear()
+
+    res = client.post("/generate", data={
+        "text": "Salam", "profile_id": english_profile, "engine": fake.id,
+        "language": "Persian",
+    })
+
+    assert res.status_code == 400, res.text
+    detail = res.json()["detail"]
+    if isinstance(detail, dict):
+        assert detail["code"] == "profile_language_rejected"
+        assert detail["language"] == "Persian"
+        detail = detail["message"]
+    assert "voice profile" not in detail.lower()
+    assert "does not override" not in detail
+    assert "doesn't support language='Persian'" in detail
+
+
+def test_a_supported_profile_language_still_drives_generation(
+    client, monkeypatch, english_profile
+):
+    """#533 is untouched: a profile language the engine *can* speak still
+    reaches it and still renders."""
+    fake = _make_refusing_engine()
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    fake.calls.clear()
+
+    res = client.post("/generate", data={
+        "text": "Hello", "profile_id": english_profile, "engine": fake.id,
+    })
+
+    assert res.status_code == 200, res.text
+    assert [kw.get("language") for _t, kw in fake.calls] == ["English"]
+
+
+def test_a_non_language_failure_under_a_profile_is_untouched(
+    client, monkeypatch, persian_profile
+):
+    """Over-matching guard: having a profile language must not rewrite every
+    ValueError as a language problem."""
+    class _Boom(_make_refusing_engine("fake-boom-2156")):
+        def generate(self, text, **kw):
+            raise ValueError("Reference clip is shorter than 3 seconds.")
+
+    monkeypatch.setitem(_tts_mod()._REGISTRY, _Boom.id, _Boom)
+
+    res = client.post("/generate", data={
+        "text": "Salam", "profile_id": persian_profile, "engine": _Boom.id,
+    })
+
+    assert res.status_code == 400, res.text
+    detail = res.json()["detail"]
+    if isinstance(detail, dict):
+        assert detail["code"] == "profile_language_rejected"
+        assert detail["language"] == "Persian"
+        detail = detail["message"]
+    assert "shorter than 3 seconds" in detail
+    assert "voice profile" not in detail.lower()
+
+
+# ── units ───────────────────────────────────────────────────────────────────
+
+
+def test_the_real_kokoro_wording_is_recognised_as_a_language_rejection():
+    # #1257's signature list never matched this — "doesn't support language="
+    # contains none of "invalid language code" / "unsupported language …" — so
+    # the provenance check would have skipped the engine actually reported.
+    assert _gen_mod()._is_language_rejection(KOKORO_REFUSAL)
+
+
+def test_a_self_describing_rejection_is_not_wrapped_twice():
+    """Kokoro already names its engine and its languages. #1257's rewrite must
+    leave it alone, or the user reads "Engine's own message:" twice."""
+    class _Engine:
+        id = "mlx-audio"
+        display_name = "MLX Audio"
+
+    original = ValueError(KOKORO_REFUSAL)
+    assert _gen_mod()._language_rejection_or(original, _Engine(), "Persian") is original
+
+
+@pytest.mark.parametrize("reason", [
+    "Invalid language code. Supported languages: ar (Arabic), da (Danish)",
+    "Unsupported language: bn",
+])
+def test_generic_rejections_are_still_rewritten_with_engine_context(reason):
+    """#1257 keeps working for the messages it was written for."""
+    class _Engine:
+        id = "mlx-audio"
+        display_name = "MLX Audio"
+
+    rewritten = _gen_mod()._language_rejection_or(ValueError(reason), _Engine(), "bn")
+    assert rewritten is not ValueError
+    assert "MLX Audio" in str(rewritten)
+
+
+# ── review findings on the first cut of this fix ────────────────────────────
+
+
+def test_a_generic_rejection_is_quoted_once_not_twice(client, monkeypatch, persian_profile):
+    """Greptile P2. `_language_rejection_or` wraps a *generic* rejection with
+    the engine remedy before the handler sees it. Building the profile message
+    from that wrapper repeated both the engine-switch advice and "Engine's own
+    message:" twice — so the profile message is built from the engine's own
+    text, not from the wrapper around it."""
+    class _Generic(_make_refusing_engine("fake-generic-2156")):
+        def generate(self, text, **kw):
+            raise ValueError(
+                "Invalid language code. Supported languages: ar (Arabic), "
+                "da (Danish), de (German)"
+            )
+
+    monkeypatch.setitem(_tts_mod()._REGISTRY, _Generic.id, _Generic)
+
+    res = client.post("/generate", data={
+        "text": "Salam", "profile_id": persian_profile, "engine": _Generic.id,
+    })
+
+    assert res.status_code == 400, res.text
+    detail = res.json()["detail"]
+    if isinstance(detail, dict):
+        assert detail["code"] == "profile_language_rejected"
+        assert detail["language"] == "Persian"
+        detail = detail["message"]
+    assert "voice profile" in detail.lower()
+    assert detail.count("Engine's own message:") == 1
+    assert detail.count("switch engine in Model Catalogue") == 1
+    # The engine's own text survives exactly once.
+    assert detail.count("Invalid language code") == 1
+
+
+def _route_remotely(monkeypatch, failure):
+    """Send the render to a worker, and fail it there with `failure`."""
+    from types import SimpleNamespace
+
+    from services import gpu_gateway
+
+    gen = _gen_mod()
+    monkeypatch.setattr(
+        gen, "_routing_decision",
+        lambda: SimpleNamespace(remote=True, label="gpu-box", reason=""),
+    )
+
+    async def _boom(*_a, **_k):
+        raise failure
+
+    monkeypatch.setattr(gpu_gateway, "run", _boom)
+
+
+def test_a_remote_language_refusal_is_a_400_not_a_retryable_503(
+    client, monkeypatch, persian_profile
+):
+    """Greptile P1. A worker's rejection comes home as RemoteJobFailed, which is
+    caught ahead of the ValueError branch — so the profile-aware 400 never ran
+    and the user was told to retry on this machine, where the same engine
+    refuses the same language."""
+    from services import gpu_gateway
+
+    fake = _make_refusing_engine("fake-remote-2156")
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    _route_remotely(monkeypatch, gpu_gateway.RemoteJobFailed(
+        KOKORO_REFUSAL, worker_label="gpu-box"))
+
+    res = client.post("/generate", data={
+        "text": "Salam", "profile_id": persian_profile, "engine": fake.id,
+    })
+
+    assert res.status_code == 400, f"{res.status_code}: {res.text}"
+    assert res.headers.get("X-OmniVoice-Retryable") != "true"
+    detail = res.json()["detail"]
+    if isinstance(detail, dict):
+        assert detail["code"] == "profile_language_rejected"
+        assert detail["language"] == "Persian"
+        detail = detail["message"]
+    assert "voice profile" in detail.lower()
+    assert "Run it on this machine instead" not in detail
+
+
+def test_a_remote_non_language_failure_is_still_a_retryable_503(
+    client, monkeypatch, persian_profile
+):
+    """Guard on the same branch: only language refusals change class — a real
+    worker failure keeps its retryable 503 and its 'run it here' offer."""
+    from services import gpu_gateway
+
+    fake = _make_refusing_engine("fake-remote-ok-2156")
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    _route_remotely(monkeypatch, gpu_gateway.RemoteJobFailed(
+        "CUDA out of memory on the worker", worker_label="gpu-box"))
+
+    res = client.post("/generate", data={
+        "text": "Salam", "profile_id": persian_profile, "engine": fake.id,
+    })
+
+    assert res.status_code == 503, f"{res.status_code}: {res.text}"
+    assert res.headers.get("X-OmniVoice-Retryable") == "true"
+
+
+def test_the_wrapper_keeps_the_engines_own_error_reachable():
+    class _Engine:
+        id = "mlx-audio"
+        display_name = "MLX Audio"
+
+    original = ValueError("Invalid language code. Supported languages: ar (Arabic)")
+    wrapped = _gen_mod()._language_rejection_or(original, _Engine(), "Persian")
+    assert wrapped is not original
+    assert _gen_mod()._root_language_error(wrapped) is original
+    # An unwrapped error is its own root.
+    assert _gen_mod()._root_language_error(original) is original
+
+
+def _row(**over):
+    row = {
+        "kind": "clone", "instruct": None, "is_locked": 0,
+        "ref_audio_path": None, "locked_audio_path": None, "ref_text": None,
+        "seed": None, "vd_states": None, "language": None,
+    }
+    row.update(over)
+    return row
+
+
+def test_the_resolver_flags_a_profile_filled_language():
+    out = _gen_mod()._resolve_profile_conditioning(_row(language="Persian"))
+    assert out["language"] == "Persian"
+    assert out["language_from_profile"] is True
+
+
+def test_the_resolver_does_not_flag_an_explicit_request_language():
+    out = _gen_mod()._resolve_profile_conditioning(_row(language="Persian"), language="French")
+    assert out["language"] == "French"
+    assert out["language_from_profile"] is False
+
+
+def test_the_resolver_does_not_flag_when_the_profile_has_no_language():
+    out = _gen_mod()._resolve_profile_conditioning(_row(language=None))
+    assert out["language"] is None
+    assert out["language_from_profile"] is False
+
+
+def test_an_explicit_auto_is_still_filled_from_the_profile():
+    # "Auto" and an absent value mean the same thing to #533; the flag must be
+    # set either way, since neither is the user naming a language.
+    out = _gen_mod()._resolve_profile_conditioning(_row(language="Persian"), language="Auto")
+    assert out["language"] == "Persian"
+    assert out["language_from_profile"] is True
+
+@pytest.mark.parametrize('remote', [False, True])
+def test_streamed_profile_language_refusal_is_terminal(client, monkeypatch, persian_profile, remote):
+    import json
+    from services import gpu_gateway
+    fake = _make_refusing_engine('fake-stream-language-2156')
+    monkeypatch.setitem(_tts_mod()._REGISTRY, fake.id, fake)
+    if remote:
+        _route_remotely(monkeypatch, gpu_gateway.RemoteJobFailed(KOKORO_REFUSAL, worker_label='gpu-box'))
+    response = client.post('/generate', data={
+        'text': 'Salam', 'profile_id': persian_profile, 'engine': fake.id, 'stream': 'true',
+    })
+    assert response.status_code == 200, response.text
+    frames = [json.loads(line) for line in response.text.splitlines() if line]
+    error = next(frame for frame in frames if frame['type'] == 'error')
+    assert error['code'] == 'profile_language_rejected'
+    assert error['language'] == 'Persian'
+    assert error['retryable'] is False
+    assert error['terminal'] is True