Ex-stutterer here. Might i add to this that prolongation isn't a technique but more of a coping mechanism. A trick so to say. Prolongation is essentially just another form of stuttering, one of the 10 most common ones out there to be precise. As for #2 she's doing it wrong because she inhales too fast and too much into her belly. It's not about sticking your stomach out (that does absolutely **nothing**) but more about inhaling slowly through the nose and out the mouth, controlling your diaphragm by letting the air rest there (so above your belly) for about 5 seconds and then breathing out slowly, resting your belly as much as possible. You can also put your hands on your ribs to get a better feel for it too. Rinse and repeat a couple of times until you feel comfortable enough to speak. If that doesn't work then slow breathing and talking on a single breath of exhaled air is your backup plan. IMHO diaphragm breathing is one of the best ways to control your breathing and stutter. It even works if you have trouble falling asleep cause by the end of your 5 minute exercise you'll sleep like a log. I do think there's a lot of misinformation about it on the internet though. Using your belly like they show in pictures and videos is not key. A combination of the right guidance, proper diaphragm breathing and the corresponding exercises, slow talking and a whole bucket of willpower is how I got over it.