Probably. And if you could accurately predict the lack of function after learning something, you'd probably dump that subject no? And you can do that with lang

Probably. And if you could accurately predict the lack of function after learning something, you'd probably dump that subject no? And you can do that with language instruction in most cases. Hell, maybe make language instruction more hardcore and immersive for those who need or actively seek it. For everyone else, it's not worth pursuing 98% of the time.