I agree that “learning your mother tongue did not require you to sit and study” is an exaggeration – my schooling included years of sitting and studying grammar

I agree that “learning your mother tongue did not require you to sit and study” is an exaggeration – my schooling included years of sitting and studying grammar during the English class for native speakers, and I probably learned to speak better as a result. However, I think at least a significant subset of grammar is only learned implicitly, never taught in school. The classic example of this is adjective order (https://www.grammarly.com/blog/adjective-order/ https://www.grammarly.com/blog/adjective-order/): native English speakers know that “the nice orange cat” sounds better than “the orange nice cat”, but most can’t explain why.