I'm not a therapist. But after receiving speech therapy (over 20 years ago), I certainly recognize his blocks and his techniques. I'm actually surprised with the number of times I've observed him drop out of something he intended to say due to anticipation of a block. Before I achieved fluency, I would frequently abandon things I was going to say due to blocks. Since becoming fluent, I refuse to let a block stop me from saying something. I want to choke someone every time they claim he's mentally deficient, and I can see that it is clearly a stuttering moment.