Well, the joke is about the relation between spoken and written English, so „how do you write [o]“ is just the same joke but in reverse 🤷‍♀️

And none of that touches my original point, i.e. that written french is syntactically different from spoken French.

Look, I have several German-French friends with whom I took French class in high-school. They grew up with two languages, their spoken French is flawless, they couldn’t write a single paragraph if their lives depended on it.