There are many stutter therapies with diaphragmatic breathing. Del Ferro therapy: you focus on the up and down movement of the diaphragm (which we see on a tv screen at therapy). And then always when we speak in therapy, we step 1: close our eyes and imagine the up and down movement, and then we speak. Step 2: speaking with eyes open while visualizing up and down movement of diaphragm. Step 3: not using any visualization.