I went to therapy, for like 4-5 years. The thing with my stutter was, it occurred from two conditions physical and psychich. After my parents got divorced it really kicked in and went from like 10% to a full 100% So, treating me would include speaking about my therapy, as well as training my breathing apparatus. I got tought, that breathing through my nose is really important and not to breathe into my lungs more into the diaphragm, so that the belly will move instead of my rib cage This way you can create an airflow much more fluent. If you have problems, try to start the sentences with an H, by just exhaling and building up the voice It may sound weird to other people because, but if you are in the flow, nothing will stop you, but getting into the flow is the most important thing. In the beginning, I was nearly singing, to keep up the airflow all the time I hope, you get all my points, and maybe this will help you a little