I would describe a speech block as: * a block is the halting of speech muscles (like lips, tongue, jaw, laryngeal or respiratory muscles) mechanically speaking * inhibiting execution of motor movements (mechanically speaking) * not initiating articulation * freezing speech structures * additionally, in my opinion, a silent block occurs without exhaling or voice production. A regular block may occur with exhaling or voice production. In this viewpoint, I consider a prolongation also a type of block * I consider a silent block the primary symptom of stuttering. Repetitions are merely secondary attention-holding struggle behaviors and a negative coping mechanism to maintain the speech rhythm in my opinion