Recently I was told that some people actually speak at 300 words a minute. I do find it hard to believe, but having sped up a tape to approximately 300 words a minute I realize that I can understand what the speaker is saying -- I just really had to focus.
Then I was looking at a book I found on my shelves: Rapid Writing in 6 Days by Ben E Johnson. He says:
Sean Shannon, a Canadian residing in Oxford, Great Britain, recited Hamlet's soliloquy "To be or not to be" (259 words) in a time of 24 seconds--equivalent to 647.5 words per minute--on British Broadcasting Corporation's Radio Oxford on October 26, 1990.
Here's the link. I'm not sure what the page is, it is lesson 7 of Extreme English. Half-way down the page is an audio link -- part English, part Polish, and two takes of Mr Shannon (of course he's a Canuck) doing the soliloquy at 647 words per minute. I got about 1 word in 30.