User Online Check
“Are you still there?” plays in the caller’s detected language
Call Hangup
Farewell message delivered in the detected language
Tool Call Wait
“Please wait” messages during API calls adapt to the language
How Detection Works
1
Conversation Begins
The agent starts in the primary language configured in the Audio Tab.
2
The Agent Switches Language
Bolna’s language-switching engine decides, turn by turn, whether the caller has genuinely moved to a different configured language. See How Language Switching Works for exactly what triggers this.
3
System Messages Follow
These system messages simply follow whatever language the agent is currently speaking — when it switches mid-call, they switch with it too, near-instantly, falling back to English if a variant is missing.
There’s no separate detection pass for system messages — they always match the agent’s current active language.
Supported Message Types
User Online Check Message
When the agent checks if a caller is still on the line after a period of silence, it sends a configurable message. Add variants in multiple languages and Bolna picks the right one automatically.
Multilingual user online check messages configured for English, Hindi, Gujarati, Bengali, and Tamil
Call Hangup Message
When the agent ends a call, it delivers a closing message. Configure multilingual variants so callers hear a natural farewell in their language.
Multilingual call hangup messages configured for English, Hindi, Bengali, and Tamil
Function Tool Call Messages
When the agent executes a tool or API call, it plays a brief “please wait” message. This message can also be configured per language.
Multilingual pre-call messages for custom function tools in English and Hindi
Fallback Behavior
When selecting a message, Bolna follows a three-step fallback:Supported Languages
System messages follow the same language the agent itself is speaking, so they cover whatever your agent supports. Automatic mid-call detection — the part that decides when the agent’s active language changes — is tuned for a specific set of languages; see Supported Languages for Automatic Detection for that exact list, and the Multilingual Support guide for the full set of languages Bolna can be configured with.Best Practices
Consistent Coverage
Add message variants for every language your agent supports. Gaps lead to unexpected fallbacks.
Culturally Appropriate
Write messages that feel natural in each language. Avoid direct translations.
Native Script
Always use the language’s native script. “धन्यवाद” not “Dhanyavaad”.
Test with Speakers
Verify messages sound natural by testing with native speakers of each language.
Next Steps
Multilingual Support
Full guide to setting up multilingual agents
How Language Switching Works
What triggers a switch, and what doesn’t
Non-English Prompts
Best practices for writing prompts in native scripts
Custom Function Calls
Configure pre-call messages for API tools
Engine Tab
Configure user online detection and timeouts

