To add Telugu (te-IN) language support to Vapi, I recommend contacting Vapi support directly. According to the [Vapi documentation](
https://docs.vapi.ai/support), you can submit a feature request specifically asking them to add Telugu language support to the Azure voice dropdown menu. Since Azure already supports Telugu (te-IN) as mentioned in the Microsoft documentation you linked, this should be a straightforward request for the Vapi team to implement.
Source:
- [Vapi Support Documentation](
https://docs.vapi.ai/support)