Great work! Easy to understand and use. Feels less like a conversation and more like a prompt and response flashcard activity. Which I personally like. I don't see the "conversation" part in terms of connecting the next language snippet in the continued context of the last.

This would be pretty awesome if you could get it to a point where the user is chatting in real time with the language AI like with https://beta.character.ai

Michel Thomas has one of the best language learning approaches. I'd recommend looking him up sometime if your in need of other ideas and inspiration if you aren't aware of him already. (Though he passed away some time ago.)

Looking forward to seeing how this develops!