Nice job. I have a bespoke GPT that I use with ChatGTP in voice chat to do language practice but I could see this being useful for beginners.

Not sure if I ran into an error or if it was the end of the lesson, but when it asked me to pronounce "I want a coffee" and I repeated it - it didn't progress any further and just sat suspended there - dev console logs:

  useSpeechRecording] Committed: Quiero un café.
  index-DkqRIC0D.js:435 WebSocket closed: code=1000, reason="User ended session", wasClean=true