[BurningFrog]

Sounds like the old trick of "write down your question, and you'll probably know the answer".

I think it works because writing (or talking) engages different parts of the brain than thinking.

[l0b0]

To paraphrase(!), in a way you're paraphrasing your thoughts when speaking. I think I do this a lot while programming, and certainly rubber ducking (or the human equivalent, a quick sanity check with a colleague) seems to be a good way to do this.