Very cool!

I could see this tool to be very useful in my Japanese studies. I only have two problems with it:

- AI feedback can sometimes be pretty overwhelming. Maybe you could implement a level selector (beginner, intermediate and expert?) so that the AI would switch to using shorter/simpler or longer/harder sentences accordingly?

- The speech to text works fine most of the time, but sometimes it gets a few words wrong. Could there be a way to correct the last sentence input?