[harperlee]

I find the same. My wife is from another country and we find she has more command of my mother language’s rules and whys and viceversa.

For example she had a hard time expressing when does she say “oui” and when does she say “si”; being such a basic word (probably learnt at age 2), she never had to sit and try to infer the rule explicitly. Whereas every french-as-second-language speaker, this is a basic (explicit) rule that has been discussed in class and memorized before being internalized.

And having the rules more explicitly in the head enables hard reasoning over them, which goes beyond intuitiveness in some contexts.