I have a rough idea of this but do you know how people who normally stutter don’t stutter that much or at all when they sing or listen to music? I think it’s because this activates the other side of your brain that’s more responsible for creativity and not so much language. I think this is a major part of the neurological side of it. I think the fix would have something to do with stimulating the creative side of your brain more than the language side but over a prolonged period of time, you see what i mean?