Probably yes, and I think this is what a lot of rich people do with their kids, at least in terms of exposing them to vastly differing languages like Mandarin a

Probably yes, and I think this is what a lot of rich people do with their kids, at least in terms of exposing them to vastly differing languages like Mandarin and English. I do wonder if there's some limit on the number of phonemes you can learn, and how many hours are required to "solidify" a phoneme. But I definitely think the idea of a "unity course" is a good one. Personally I had a French "class" in elementary school, where I barely learned anything - I certainly can't speak French - but I can pronounce French words better than I can pronounce any Spanish words (despite three years of Spanish class in college). Those French classes were basically just learning to count to 100 and singing songs like "alouette."