Thinking about this a bit more, I realized that Duolingo, the language learning app, does exactly this.
It breaks up a large task, learning a language, into smaller bite-sized chunks. It rewards users with coins that can be used to do power-ups. It turns learning into a rewarding game.
Perhaps this principle can be applied to other domains as well.
The word you're looking for is "Gamification" and I honestly, I fucking hate it. The problem with Gamification in this context is that apps like Duolingo that uses Gamification to award you good boy points (daily streak) in the form of streak building mainly to build up "good habits". Unfortunately, the reality is that there is only so much what one app can do before it starts holding you back and become detrimental, but because of the gamification aspects of an app and how some people really really want their good boy points they don't want to abandon it and deep down, they probably don't want to. Now some people just end up thinking that one app is the one and be all solution and end up being "expert beginners" while in reality, they had to abandon it and do something deeper (like reading an actual book in another language) or else they'll never learn to being competent.
You can even take this further with reading books. Sure, you can get a star by reading a book for like an hour a day...if you're using Apple's iBook or whatever. That just means you're locked out of other books not on that platform or books you have in other unsupported formats or gasp physical books.
If I'm understanding you correctly, you're saying that gamification is addictive and traps people into the small catalog of gamified apps? While I agree that a tolerance to more "painful" material is useful for broadening your reach, it's still possible to do both. To value gamified apps for their tight feedback loops, while being conscious that there are other materials out there that may provide other benefits despite not being as gamified
do you really feel like you learn a language with duolingo though? everytime ive tried to learn a language i got much further doing it by studying a book.
so... repetition I find is very important for speaking and writing. Duolingo nails that. In the same way German class in high school did, hours of practice really helped my speaking. Now I can't really put together sentences - but I have a decent shot at deciphering my mom while she speaks to my grandomther in german, or reading an article. So I think duolingo attacks that nicely. If you want a lot of vocab and reading comprehension I think books are good for that.
My friends that are in med school all use spaced-repetition to cram information into their memory banks, and the app they use (Anki) lets users share flashcard packs. Incidentally, aside from medschool-related packs, there's also packs for learning most languages. I don't think you can ever learn a language through spaced repetition, but it's certainly useful for expanding your vocabulary (learning new words). I started out with Duolingo but switched to Anki because I'm learning a tonal language which doesn't quite sound right with Duolingo's TTS (and the Anki card packs are accompanied with recordings of real speakers).
..and yet I still pop into Duolingo every day though to get my good-boy points :)))
It breaks up a large task, learning a language, into smaller bite-sized chunks. It rewards users with coins that can be used to do power-ups. It turns learning into a rewarding game.
Perhaps this principle can be applied to other domains as well.