I mean it only works with nouns that are not ending on vowels and also not every noun works good.
But I heard this from people all over Germany. Mostly in a mocking way, like someone was eating too much and complaining about stomach pain:
“Oh, tut dir der Bauchi weh?”
That sounds really wrong. Is that a southern thing?
Yea it’s definitely a dialect thing but a rather common one. I don’t know where it is spoken most tho…
I mean it only works with nouns that are not ending on vowels and also not every noun works good. But I heard this from people all over Germany. Mostly in a mocking way, like someone was eating too much and complaining about stomach pain:
“Oh, tut dir der Bauchi weh?”
Other commonly used examples I can think of:
I’ve only ever really heard it for a handful of very specific nouns, like Maus -> Mausi as an affectionate nickname
I just updated my answer with more examples but I think you are right with the nickname thing