I think the myth that stuttering is a purely psychological issue has already been disproven. Rather, stuttering has a psychological/emotional component, but no more than anything else. When we're stressed out, grieving, excited, anxious, nervous, feeling adrenaline, these emotions effect us in a myriad of ways, not just speech-wise. Consider sleep patterns. When you're stressed you sleep worse. You also stutter worse. >here have been studies which show that stutterers have less blood flow to the broca... then why is it that stutterers stutter even if they have pre-formed a sentence in their heads Because it's a motor control issue, not a strictly stringing-words-together issue. It's like asking why people with tourette syndrome still fling their arm when they have already planned not to do so. It's not something they/we can control, and that's not a failure to just think 'I'm not gonna do that'. >Some stutterers claim that they can speak properly by themselves, but stutter when they talk to other people. So could it be that the problem is the not speech itself but another pressure? Of course not. Everyone feels social pressure and anxiety and stress. Only *we* stutter. Naturally, removing any necessity for non-verbal communication frees us up from a lot of tangles. I think people often view this from the wrong angle. It isn't, "We only stutter when other people are around, therefor it's all in my head." It's actually, "I stutter worst of all when I'm thinking of a million different things, like social cues and facial expressions and how I'm being perceived, and whether or not I'm being understood, all while overcoming insecurity, because also my bangs look dumb." That's a lot of brain work! How can it possibly overcome a disfluency when it's expending energy on everything else. We severely underestimate the vast difference between speaking to no one and speaking to someone else. But I do like referring to this: >A study looked at the brains of 94 stutterering and non-stuttering children and adults and found that the baseline brain activity--the way neurons fired signals--was different for stutterers in the region of the brain associated with regulation of speech production, attention, and emotion. [src](https://jamanetwork.com/journals/jamapsychiatry/article-abstract/2587079) They're all intricately linked, presumably.