What I learned about stammering was that, when as a young child you lose the confidence of anyone who wants to listen to you, you lose confidence in your voice and the right to speech. And a lot of the therapy was saying, 'You have a right to be heard.' ↗
When I was growing up my mother would say, 'Your dad may have to learn about being a father because he lost his own and that would have affected him'. ↗