You have an excellent knowledge of the conventional information pushed everywhere by the system! But have you ever thought about those researchers? Have you ever met them in person? I have. They all stutter themselves and do what the medical system is paying them to do. Nothing personal. It’s just business of making money for the budget of the system:-( Now, if you allow me, I’ll write my understanding of two CONVENTIONAL theories that you mentioned. 1. There is not cure or treatment for stuttering. Yes, for sure. There is no cure! But why? Because there is no sickness to cure. Stuttering is not a medical condition. People who stutter are totally healthy. They just make speaking mistakes at times. Right? 2. There are differences in the brain activity during speech in a person who stutters and doesn’t. This is also correct. But why? Because these two individuals do totally different things while speaking. This is why, their brains react to their different actions in totally different ways. When a normal speaker performs a normal speech action, he activates the right parts of his brain. But when a stutterer does something incorrectly, he activates different parts of his brain and the “speech areas” remain inactive.