Other replies mention the atypical preparedness of presentation text; but I have noticed what you describe in normal life, in normal conversation: some people do indeed seem to speak as if they'd had a chance to revise the sentences / paragraphs in advance. Is it that they care more, and a lifetime's practice has resulted in that kind of automatic organization?
Quite often, I'll have run through a whole series of variations on the probable avenues that a conversation or meeting could take. If you deal regularly with the other party in the conversation, you can often predict with pretty good accuracy what they are going to say. Most spoken communication is just trudging through the same well-established ruts, and throwing out the same sound-bite loops.
Eventually you get to the point that you know that when subject X comes up, Bob is going to deploy his well-worn chestnut that you've heard 147 times before, and you can damn-near repeat it word-for-word.
> Most spoken communication is just trudging through the same well-established ruts, and throwing out the same sound-bite loops.
You're hanging out with the wrong people. Or something.
> when subject X comes up, Bob is going to deploy his well-worn chestnut that you've heard 147 times before,
You should stop hanging with Bob. There are other people out there who have real conversations about what's going on with them, their view of current events, their new ideas for what ought to be done, their new inspirations. . .
I think the more likely and plausible explanation for why some people sound more prepared when speaking is because... they simply are better at it. They've practiced thinking through things, and are adept at putting thought into words. They've developed the think-and-communicate muscle, through lots and lots of practice, and now they can use that muscle with greater effectiveness than your average bear.
