Read this book The King’s Speech! Basically if you notice when you stutter, it’s because your words come out too quickly, and there are involuntary contractions of the diaphragm as a result. So the key here is to prevent the diaphragm’s contractions which cause the stutter. A quick fix is to take a deep breath and exhale as you are speaking, to let your diaphragm move smoothly, and make this into a habit. But it takes time to see results, so just press on! If you have any more questions, I’ll be more than glad to answer!