I'm American, and I find I stutter less when I put on a French accent or a Southern accent (I'm from the Northeast). The logical explanation is that any sort of "new" way of talking throws your brain off a little and gets rid of the stutter temporarily (similar to the way SpeechEasy works - delayed auditory feedback fixes it for a little while until your brain adapts). Except for whatever reason English accents, specifically London, have always made me stutter *way* more. I have no idea why. Sometimes I feel like stuttering is the most inexplicable thing on Earth.