I agree about the accents. I don't really notice huge differences between the speech of Pittsburgh and DC and here, for instance, but I am told when I am in Pittsburgh or DC that my accent is very strong. In Pittsburgh, when I ask for coffee, I often get Coke.

I was raised in the UP and I do know there are some definite differences in the pronunciation of vowels between the UP and here, as well as the length of the ending of some words. I may still have a smattering of that left in my speech, but I tend to be a parrot and pick up from people I interact with.