Have you ever watched a child learn language? They're not conscious of grammar at all. It's basically impossible to correct them, the just ignore you and keep on saying the wrong thing. Eventually they figure out the right thing themselves.
Have you watched an adult learn a pidgin through immersion? It has a similar character, because there is no French academy, Latin teacher, or privileged register of English involved, and there is no methodology.
I wonder where we got the idea that the only way people learn languages after their first is through school.
