"I do not think a repetition is done to avoid a block." Why don't you think a repetition is done to escape a block? Researchers state that blocking and repetitions are core behaviors for stutterers. In my opinion that is only one theory. Another theory is, that repetitions are secondary behaviors whereas blocking are primary behaviors. Because we 'repeat' a syllable, like this: super-super-supermarket. So in this example, we are stuck at the letter 'r' (from super) and by doing repetitions we go back to the first letter 's' (from super). Why do we go back to the first letter? The question is, at the letter 'r' (in super), why do I go back to the first letter 's' (in super) instead of continuing to the next sound? I believe it's because we would otherwise block on the letter 'r'. So the statement is therefore valid: we do repetitions to prevent (or escape) a block. The opposite is also true, we block to escape a repetition (i.e. from embarrassment that repetitions elicit). What is your argument? Why don't you think so?