Tavus stock voices in 16 languages vs Sume TTS language mismatch 409
Tavus auto-localized 16 new stock voices (Sep 9, 2026). In Sume, a voice and text language mismatch returns 409 unless you confirm. How to avoid wasted renders.
Tavus's changelog entry for September 9, 2026 says it added 16 new stock voices that auto-localize to 16 languages, and that all 42 supported languages are covered. Sume treats language mismatch as a hard check: if the text language does not fit the voice, the TTS call returns 409 tts_voice_language_mismatch, and you override it explicitly with confirm_language_mismatch.
The facts
Tavus facts are from its changelog; the Sume behavior is from its TTS API notes.
| Fact | Value |
|---|---|
| Tavus new stock voices | 16, auto-localized to 16 languages |
| Tavus supported languages | 42 |
| Sume mismatch response | 409 tts_voice_language_mismatch |
| Sume override | confirm_language_mismatch |
| Sume TTS price | $0.0475 per 1,000 characters |
Why the hard stop helps
A mismatch is usually a bug in a pipeline: Korean text sent to an English voice, or a template that did not switch voice per locale. A 409 stops it before you pay for a render. Override only when the accent is intended.
Related caption behavior is similar: Korean text on a Latin caption style returns 400 caption_hangul_text_latin_style instead of producing a broken video.
A localization checklist
Pair each locale with one voice in config, test the first line with TTS at fractions of a cent, then submit the avatar video. Check the avatar video docs for the caption language field.
Auto-localization is convenient but not the same as a human read of your script, so review audio for names and numbers.
Sources
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