I just had this situation happen over the weekend. A big group of folk out at a bonfire and I was asked where I was from. Was trying to say an hour 1.5 North West but began blocking in anticipation of a stuttering episode so I filled with lots of interjections and other easy-onset techniques. I can sense when I'll stutter especially if I have high anxiety and stress. I started to stutter a little and stopped myself multiple times resulting in blocks. The more I speak the more I stutter so I've developed some poor habits like blocking and interjections to buy myself some time while mentally working on getting the word out. Often times I'm so focused on how to deliver my words that I forget what it was I wanted to say in the first place and I loose my rhythm and spot and then people just think I'm stupid and so I shutdown and go mute the rest of the night.. it's a real struggle trying to communicate with normalcy. My stuttering gets really bad when I need to think on the fly and have no time to develop an answer prior. But I suppose that all takes time and experience in socal situations. In short, yes blocks are a part of a Stammer. Blocks, repetitions, and prolonging words are all apart of it some people have it all :) yay