Before coming to the USA for the first time I read the following in a guide: "Americans often communicate via inflected grunts and groans, such as "uh-huh" for yes and "uh-uh" for no.
As an American who does this in pretty much every conversation I have, this is a difference I would never have thought of. Semi-related: Do other countries have fragments of speech used as filler such as "like" and "you know"?
Also there's a one-to-one relationship between english's use of "like" as a filler by our use of "genre". In this case, "genre" means "similar to". So one could say "J'ai genre... mangé une criss de grosse poutine" in the same way an english speaker would say "I have like.. eaten a fucking huge cheese-and-gravy covered bowl of french-fries".