I think a good hefty percentage of Americans have some kind of accent that creeps in when they aren't paying attention. I do. I have KY/Appalachian roots, and I catch myself saying the darndest things. Like "winduh" instead of "window." Or "fill" instead of "feel."
Of course, the city of Louisville is properly pronounced "Louvul." I live near Centerville, so natch, I call it "Centervul." Yes, people give me strange looks.
One thing my hubby teases me about is calling the TV remote a "flipper." He said he'd never heard anybody else in the whole wide world say that, and I'm sure that's true. But it still makes perfect sense to me, as in, "flip" the channels, as you would have done on an old-fashioned TV with a dial. I think I got the term from my grandma.
Everyone knows that a "flipper" is really a spatula.
