I'm always a bit weary of theoretical stuff like this. The best way to learn a new language is to move there (preferably somewhere where people don't speak or don't want to speak your native language). I know people that didn't speak a lick of Spanish, moved to Spain, and in a year they're basically fluent. Of course, still struggling with stuff they might not be used to: gendered language, conjugations, and so on. But overall, able to be fully understood by native speakers.

Theoretical educational frameworks don't replace the day-to-day struggle of trying to get shit done. (Doing this is, of course, extremely uncomfortable, and people will avoid it at all costs.)