There was a quiz in the NYT a year or two ago that did an astounding job of this without any AI -- it suggested two places for my upbringing based on what words I used "pop" vs "soda", whether I pronounced "pin" and "pen" the same or not, etc -- and the two suggested places happened to be where I grew up and where my parents grew up (which probably influenced my speaking by copying them as well as my peers).
Well, that's a decision tree! An algo that arguably falls under ML :)
Seemed to me like it was some sort of bayes classifier. Either way, clearly classic ML.
That would be fun to use. Talk to an AI for a minute and have it figure out where you're from. Kind of like an audio based 20 questions. It would also be entertaining to try and trick it.