In my experience, if I do a speech block: * I stop executing speech movements * I don't initiate articulation If I tense my throat muscles, even to their maximum extent, this tension alone will never result in a speech block. You can test it out yourself, by doing this exercise: (1) in this moment, tense your throat muscles as much as you can, (2) and then say the letter /P/ or /A/. As you've just experienced, you didn't block. So, the conclusion that I draw is that the tension of the articulators, can by itself, never lead to a speech block.