> My daughter learned to say "chouette, c'est joli !" in her french class, which is preposterous and almost akin to saying 'Jolly gay, old chap!' in English today.

Don't be so harsh. I would not be surprised to hear a child (~6/8 years old) say that, assuming some kind of polite/policed family background.

> Yes, they don't teach you the "on a...", "faire le truc avec...", "ouais" and "ca marche"

Imagine us watching Stringer Bell from "The Wire" for the first time. Or listening to pop or rap. Or chatting with native speakers.

We just have more exposure.