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?

Edit: I am already aware of Anki, although I don't think it alone is enough for me (plus I can get unmotivated to do the cards for a day and then I have to play catch up)