I have a theory that it has to do with either a specific brain region malfunctioning or maybe an interruption in the communication between brain regions that work together to produce speech. I’m taking a psychology class, and we’ve learned a lot about the brain. Broca’s area is the main region in the brain for speech production, so maybe this area is different somehow in stutterers. Or maybe it has to do with peripheral nervous system signal interruption instead. I don’t know, but I’d love to do research in this area someday!