Ubiq, i should have been clearer. I was referring to what happens lemaysoh – public elementary schools teach grammar,and the vast majority don’t absorb it. Those who are bookish will have good grammar regardless. I’ve always said that if you teach grammar methodically, it never sticks; when i was a kid, i had perfect grammar because of “what sounds right,” since i grew up in a literary house with a father who was a professional writer.
Im yeshivos they teach dikduk, and who remembers it? The handful of grammar people.
Public schools might teach it, but it’s entirely ineffective. Those who speak and write well just do; these are things that are more environment/genes based.