Take this with a grain of salt because I’m not an expert or a stutterer, just the partner of a stutterer who has found it interesting enough to read a bunch of research. Stress exacerbates all kinds of problems and conditions. So it’s absolutely possible to have an underlying dysfunction or anatomical difference in your brain that gets “triggered” by a certain level of stress, and that stress level might be higher for some people than others. My husband stutters in nearly all situations (unless he doesn’t talk!) so it seems to take very little (basically just talking) to cause him to stutter. But for other people it seems like much higher level of stress for stuttering to “kick in.” That doesn’t mean stuttering is psychological, though, any more than having an autoimmune condition that gets triggered by stress is. I just think that’s important because if stuttering is caused by being more stressed or more anxious or more insecure than other people, the implication is that stuttering is your own fault. And it’s really not. Just like a person whose psoriasis outbreak is triggered by stress didn’t cause their condition by being stressed. Their body just responds to the same stresses all people experience in this way because of underlying physical issues.