One language per Finn
Each Finn has one language. The Finn listens for that language and speaks it for the whole call.
Set it in the dashboard: click Edit on the Finn's builder page, then Call flow → Identity → Default language, and pick from the list. Through the API, set language on api-finns, for example "Hindi". It defaults to English.
What has to match the language
Changing Default language doesn't rewrite anything else. Check these yourself:
| Part | What to do |
|---|---|
| Voice persona | Pick a voice that speaks the language well. Use the Language filter in the voice dialog. See agents-voice. |
| Welcome message | The Finn speaks it word for word, so write it in the Finn's language. See agents-welcome. |
| System prompt | Write it in the Finn's language, or at least tell the Finn to answer in it. |
| Knowledge base | Prefer documents in the Finn's language. See agents-knowledge-base. |
Translating the personality
When you build a Finn from a playbook and its language isn't English, the personality step offers:
- Translate personality to {language}, which translates Role & identity, Tone & style guidelines and Response guidelines into the Finn's language. Role & identity and Response guidelines must be filled in first.
- Translate to {language} next to the welcome message, which translates that message.
Read the translation before you save it, and have a native speaker check anything callers will hear word for word.
Callers who speak different languages
Because a Finn uses one language, serve each language with its own Finn:
- Build the Finn in one language and test it.
- Use More actions → Duplicate on the builder page to copy it.
- In the copy, change Default language, the voice, the welcome message and the prompt.
Then route each language to its Finn:
| Direction | How |
|---|---|
| Inbound | Rent one number per language and create an inbound deployment for each Finn on its own number. See quickstart-inbound. |
| Outbound | Split your contacts into one audience per language and deploy each Finn with its audience. See outbound-campaigns. |
Each Finn then has its own prompt, voice, knowledge base and post-call questions, tuned for its language.
Testing
Test every language on a real call with Test → Phone call, ideally with a native speaker. Listen for how the voice handles names, numbers and dates, and read the transcript in call-logs to check speech recognition. See agents-testing.