Some of the intensive programs (McGuire, DelFerro) evolve heavily around the breathing concept. I did the McGuire Programme and got learned diaphragmetic breathing / costal breathing. It did help reduce my stutter tremendously. It's definitely true that it is hard to do this in the heat of the moment, so it needs a lot of practice to get comfortable enough to take your time and apply this technique. When I block, I release the block by exhaling and taking a deep costal breath again. After some time and practice I manage to time the breathing in places where it is normal to pause, e.g. end of sentences. Although I have to admit it is hard and requires a lot of discipline to make it a habit of always speaking with this breathing technique. I notice that when I struggle more with speaking and remind myself of the breathing, it does help though. Some links: [https://www.reddit.com/r/Stutter/comments/11fb2gy/the\_importance\_of\_breathing/](https://www.reddit.com/r/Stutter/comments/11fb2gy/the_importance_of_breathing/) [https://www.reddit.com/r/Stutter/comments/uw6wsl/breathing\_from\_diaphragm\_tips/](https://www.reddit.com/r/Stutter/comments/uw6wsl/breathing_from_diaphragm_tips/) [https://www.youtube.com/results?search\_query=diaphragmatic+breathing+stutter](https://www.youtube.com/results?search_query=diaphragmatic+breathing+stutter)