I tried your app a while ago and I love the concept. I think the real sticking point for me (and maybe many others) wasn't that it wasn't engaging enough, rather that my partner just didn't want badly enough to learn my heritage language. At that point it was better for me to just go back to grinding Anki and consuming content. Automatically losing two users if one drops off is rough.

Thanks for the feedback, I'm trying to sort of post-mortem and I think that's always been a major point I thought I could overcome.