practicing speaking with a reduced speech rate can help the brain repair the stuttering. check out this video that explains this plus talks about other research findings. Its kinda long but worth as it reveals some research findings. https://m.youtube.com/watch?v=3XeTXge6s3A&pp=ygUgaG93IHRoZSBicmFpbiByZXBhaXJzIHN0dXR0ZXJpbmc%3D