"Do you often feel or know that you will stutter". I don't think anticipation is the right word to describe this. It's more like a sixth sense or intuition. When we think of the words we want to say and think of vocalizing them, we get a feeling that something isn't quite right. We've experienced blocking so much that we've learned to recognise the slight signs that a block is going to occur. Whether that be us identifying slight tensions in our vocal chords or speech articulators when we think about saying the words or we can feel a slight shift in our brain, like a misfire. It's really hard to describe the feeling or sensation being referred by this question but I know that all stutterers know exactly what's being described. Especially moderate to severe stammerers.