I would like to learn a couple of languages (polish and Japanese - I already learned Spanish to a decent degree) but it seems like every solution is closed source.
I would use books but listening (and speaking) are very important and books won’t help with those.
What would you guys recommend?
so what is?
Comprehensive input:
www.dreamingspanish.com
Comprehensible input, lots of it. Classes, grammar books ,flash cards, and the like are useful supplements, but only a lot of time with the language works in the long run.