I was once explained by a psychologist specialized in brain damage that stuttering by general rule is thought to be the poor connection between some of the speech sectors of the brain. Speech works, but there is a low flow of energy between them. He explained how these sectors can be properly connected with practice and determination until your brain gets used to it and makes it a normal routine because he has seen improvement with patients with severe cases of brain damage or neurological issues. It would be like redirecting the necessary amount energy into each place. This could be achieved with different speech techniques, if you practice them enough that you incorporate them into your life. But it’s not an easy path. Sorry if the explaining was a bit off, my native tongue is Spanish.