I will try to elaborate it. What if I'm walking, how did I move my legs? I'd say that we chose to move our legs, because 'the decision/instruction' is in our control. We cannot directly operate the feedforward system, like we cannot consciously send electrical signals to our brain and move each of the 100s of muscles consciously (this is not in our control), however, we can decide/instruct the action to move legs muscles when walking (or in the case of speaking, to move mouth muscles). What I meant with my previous question is, whenever you experience a prolongation/block, do you then decide/instruct to execute speech movements (for example, instruct your brain to move the lips or tongue needed for speech production)? Or do you avoid 'instructing to move the lips or tongue' during a prolongation or block?