Pretty cool, I had a little chat in german and then the last translate button wouldn't work, the chat disappeared after I clicked around the rest of the interface. Main thing that seems missing is there is no feedback on the grammar and spelling or things that should be said, so perhaps you need a second model + prompt to analyse the inputs of the user in relation to the conversation and critique it as a language teacher in terms of spelling, grammar and contextual relevance, suggesting an alternative that the teacher would have said?