So, how common is the word ‘purty’ where you live?
As far as I know it’s mostly Hollywood. I have heard people say it but it’s not the natural way they say pretty. It’s an intentional corruption of the word that mimics Hollywood.
It’s kind of like fake pirate talk - “Aye, Matey, shiver my timbers.” There are a number of terms and phrases that came from Hollywood. People sometimes use them, but it’s not their natural way of speaking. They are just messing around.
If there is any place where people naturally say purty I’m not aware of it.
Mostly just movie and TV westerns and The Beverly Hillbillies.
“She’s done up right purty “
Possibly some use by others, but as NN said, in an emulation mode.