According to a similar bug report in the Vapi Discord, this exact issue has been reported before where selecting "role german" results in Spanish output. The most effective troubleshooting step is to check your language configuration settings to ensure both the transcriber language and voice model language are properly specified and match.
Try reviewing your API request payload to verify all language parameters are correctly set, particularly checking for any mismatch between input and output language settings.
Sources:
- [Discord bug report](
https://discord.com/channels/1211482211119796234/1328595920899674152)
- [Language configuration guidance](
https://discord.com/channels/1211482211119796234/1270786139355090995)