Does anyone know if livekit returns the detected language when using STT. I do know that the stt vendors return these in their response. I couldn't find any thing related to any language param in the docs also.

No, there's nothing specifically in the LiveKit framework that accounts for the detected language in STT. Individual plugins may expose this, but it seems to be uncommon.

The turn_detection model relies on the response from STT for the language used. If unsupported language (for EOU) is used in STT, then it throws an error/warning that hi-IN is not supported, which it gets from STT