It’s worse than that, they’re separate languages. I work with a bunch of Italians, two of them are linguists, and they despair of talking to people from the opposite end of Italy to them. “They talk so weird!”
I’m supposed to be going to Southern Italy at the end of next month (looking a bit unlikely now) and I tried Duolingo for a while until I was told that they have a regional dialect so there’s no point.
I know a few curse words though, so that’ll do.