Other than with like a PDF of a textbook (or a physical version thereof), I don’t know many FOSS apps/sites for learning a language whether its a fringe language with few resources like Te Reo Māori, Irish, or Georgian or a major language like German, French, or Spanish. Have y’all seen any sites or apps for this?
I will definitely be considering LWT when I look for apps to self-host once I move out of my current place (long story). Might even look into developing a better UI if I get the time.