This is something people will sometimes say to me in response to a question. It’s not a double negative in the grammatical sense, which is really a positive (“you can’t not do it” for instance) but a negative stated twice for emphasis. I think it’s mainly a Southern thing, like saying “bless your heart”. As I’ve mentioned before “bless your heart” can be a veiled insult, but even though people have come to assume it is sometimes it’s a genuine expression of concern and sympathy. On the other hand “No, uh uh” always feels to me like it’s an insult. It comes across as, “No, and you’re stupid for asking.” That would explain the repetition for emphasis. I can even believe it started as a response not only to stupid questions but to stupid questions from people who were too stupid to take “no” for an answer, so the repetition was designed to throw off potential objections. That may explain the origins, but I think it’s survived as a kind of verbal tic. It gets used as a response even to intelligent questions. And by intelligent questions I don’t mean “What’s the sum of the square root of the hypotenuse?” but questions where the answer isn’t obvious. Maybe I’m being overly generous in my definition but I think “Where’s the bathroom?” is an intelligent question when there are no signs around that point the way. A dumb question is when you walk up to a floor display toilet in the hardware store and ask, “I’ve gotta go, could you turn around?”
“No, uh uh” annoys me when it gets used at times when I don’t think it’s warranted.
“Can I leave through this door?”
“No, uh uh.”
This was in an office. There was a door behind a receptionist that I knew led to the building parking lot and would have saved me the trouble of winding my way back through the building to get to the entrance. I think it even had a sign over it that said “EXIT”. It didn’t have an alarm or a padlock or something that said “Beware of the panther”. Maybe it was booby trapped, but how was I supposed to know that? The point of a booby trap isn’t to catch boobies, which are mostly found in the southern hemisphere anyway, but to trick unsuspecting people into being trapped. They should be called smarty traps, but that’s another story. Since there was no obvious reason why the door behind her couldn’t be used as an exit it wasn’t stupid of me to ask if I could leave through that door. Don’t you agree?
Please don’t say, “No, uh uh.”