I'm gonna come across as a complete jerk but this is just my ''theory'': Alot of people in the stuttering community (and this sub in particular) like to blame their stuttering on external things, genetics and so on. I truly believe genetics does play a role right but i have the feeling that in the end it is something that we do to ourselves (as you said, something that over a long time has manifested in our brains). It is easier to believe that our brain is making us stutter and therefore we can do nothing about it and just have to accept it while in reality there are people who have overcome the problem and that really keeps me going and makes me believe that it CAN be overcome and that the root cause is not brain damage or something but something we make our brains do intentionally (again whether that is consciously or unconsciously) That ''something'' can be vocal cords tension or putting too much tension on your chest area which constricts the airflow and so on, there are people who stutter because they had a stroke or something similiar or being borderline retarded (not meant in a negative way) but i am talking specificially about people who developed stuttering into their natural speech and are most likely unaware of what they are doing to interfere with the speech production.