Great summary, congratulations!! This was made by me, and I am just re-writing the stuff: Reinforcing: Stuttering is an extremely complex and multidimensional disorder, which means it does not have a single cause. Everything suggests that genetic/hereditary factors are important, and so far, this is our biggest certainty regarding the causes of stuttering. However, we do not have a complete explanation with scientific evidence of how this genetic pattern interacts physiologically and behaviorally to give rise to the symptoms of stuttering. Therefore, the only thing possible at the moment is to think of explanatory theories of stuttering that bring the condition the greatest amount of evidence regarding stuttering and the characteristics it presents. The two-factor theory by Genne Brutten & Shoemaker (1967) is old and considers two factors for stuttering to happen: 1. The genetic disposition (the first factor), which facilitates the effect of speech disintegration through negative emotions. 2. And classical conditioning: which determines which environmental stimuli will serve as triggers for negative emotions and, consequently, increase the chance of speech disintegration. This is their theory. Now the rest is my own assumption based on things I’ve already read, and you can draw your conclusions: The second part is the one I included regarding the motor behaviors that people who stutter engage in to overcome stuttering, and which actually hinder and worsen fluency. Such as applying force to the mouth, tongue, neck, diaphragm, among other mechanical movements that "supposedly" help speech. If people who stutter recorded themselves speaking, they would notice that in the moments they are more fluent, it is not about applying force and does not involve unnecessary movements; it is simply speech happening naturally, as in any other person who does not stutter. These mechanical behaviors vary from person to person and are reactions to stuttering that the person even learns on their own; however, such reactions are little or not functional. Over time, these forced mechanical reactions accumulate, speech becomes extremely self-conscious, and loses its naturalness, since the person who stutters believes that fluency is something they achieve mechanically and through motor movements. In other words, they replace the fine, automatic, and involuntary motor control of speech, which simply "flows," with gross, voluntary motor control, which only hinders it. This other factor can add to what intensifies the difficulties in stuttering. Clearly, these are theories, but they bring an interesting point of view. Speech is an extremely complex behavior in itself, and it is likely that the explanation of the causes of stuttering is a puzzle of many pieces that we will have to form over time with the scientific advances of the future. Some theories will fall completely, others partially, and others will remain. This one made a lot of sense to me with what I understand about how stuttering works and what I’ve observed in my own behavior, but again, it is just a theory, and reality must be much bigger than that.