I think I understand a desire for "calm" learning. I'm not especially interested in learning a language right now. However, I do generally have a distaste for "gamified" learning, and, separately, I feel distracted by things I feel are not very fulfilling, but are addicting (namely, scrolling through news, social media, or videos on my phone).

I won't say what you are building is a mistake. But just based on what you described, if I were interested in learning a language through your app, I would not just be comparing it to other language learning apps, but I would also be comparing it to language textbooks/workbooks, classes at a community college or MOOC, or language courses on DVD/CD/YouTube/etc. I guess I think that apps are good at gamifying things, if that were to be a goal. If you are stripping that away, what makes your app unique compared to all those other resources? How does your app replace or supplement other things?

And to be clear, I imagine there could be plenty of things that make your app unique! I just would want to know what those things are before diving in.