YouTube auto dub in 27 languages: how many can you voice on Sume?

YouTube's blog says auto dubbing is available in 27 languages. Sume's workspace voice library tags 16: English, Korean, Japanese, Chinese, Spanish, French, German, Portuguese, Italian, Hindi, Dutch, Polish, Russian, Swedish, Turkish and Tagalog. The two numbers measure different things, so do not read the gap as a feature count. YouTube dubs a video for viewers. Sume gives you an audio file you place yourself.

Why the tag count matters

The 16-language list is the tag a saved voice carries, and it matters for one rule. When you ask TTS to speak a language that does not match the voice's tag, the API stops with HTTP 409 tts_voice_language_mismatch before it creates a job or charges. In the MCP tool the same case returns a warning that needs your confirmation, and you retry with confirm_language_mismatch: true only if you mean it.

What to check per language

Voice choice is not the only limit. Set language on every non-English request, because an omitted field defaults to English at the provider. Sume infers Korean and Japanese from a transcript written only in Hangul or kana as a fallback, and does not translate anything for you.

• List the languages you want, then check each against your saved voices with voices_list.
• Run a short test line in each language and listen before you commit a full script.
• For a language outside your voice tags, use a different voice or leave that track to YouTube's auto dub.
• Keep the translated script as your own text. Sume speaks what you send.

The numbers, read 2026-10-06:

Reading the gap honestly

A language that appears on one list and not the other is a prompt to test, not a verdict. Sume's list is the tag on a saved voice, and TTS itself takes a language field of 2 to 16 characters, so a language you can type may still need a voice that suits it. YouTube's list says nothing about voices you can pick.

If a language you want is missing from your voice tags, make a short test file before you plan the project. Listen for the accent and the pace, and ask a native speaker to check the lines before you publish.

For a viewer-facing track the lowest-effort path is YouTube's own dub. Use Sume when you want to write the translation, pick the voice, and publish the audio as your own custom dub.