I've spent a few hours talking with Peter, and he talks in well-formed thoughts in well-structured sentences. A lot of other people, probably me included, wander a bit verbally. Peter doesn't.
Agreed. No one is doubting his ability to form sentences. Rather, he packs so much into each sentence that I question my ability to keep up.
Every sentence he said (as well as his responses in the AMA) was a a complete idea, full of insight and depth. Mere mortals, like yours truly, need to take a couple minutes to process examples and counterexamples, to define the assumptions made, to wonder at the implications. You want him to speak more on the subject.
Instead, it's so obvious to him that he continues speaking and you've just missed 3 more profound statements. Makes him fascinating to listen to.
You can see a transcript of a conversation I had with him here: http://www.cnet.com/news/talking-tech-with-peter-thiel-inves...