I've thought about this a lot since reading the book *The Body Keeps the Score*. The writer is one of the world's experts in trauma. And he talked about how in patients with PTSD, the Broca's area literally shuts off. They have brain scans of this and everything. I haven't seen any research linking this to stuttering, but there could be a similar mechanism happening. For example, I started stuttering after moving to the US from France where for a year I was in hell not being able to communicate with anyone. I also had a few mishaps because of culture differences