In Cajun country your grandparents most likely would be called Mawmaw and Pawpaw.
I'm not sure how all this works with the ethnographers, but my family is from north Louisiana, and I remember calling one of my greatgrandfathers Pawpaw. He was originally from Mississippi, but I can't quite remember where. Mawmaw had passed before I was born. They weren't Cajun (Acadian), but were Scotch-Irish.

Which sort of brings me to the euphamisims we use for when someone dies. We NEVER say so-and-so died. They "passed."

One of the things I've noticed is the way people pronounce the "ou" or "oa" combination, as in the word "house" or "coast". I'm not quite sure how do describe it, but the "ou" sounds more like the vowel in "ouch". And in coast, the o is more a round "oh" sound.