Why some languages sound so fast

Interesting study on the speed of speech across different languages:
http://www.time.com/time/health/article/0,8599,2091477,00.html

I haven't tried to find the actual paper in Language. And although the conclusion of the article is thought-provoking, I think there are some questions that can be raised as to the methodology. First, as one of the commentors noted, they only tested 8 languages, then seemed to make the generalization that the results from testing those 8 languages applied to all of the world's languages. This may be a misrepresentation by the Time Science writer, and may not be present in the actual paper.

A second question I had regarding methodology was the specifics on how they categorized syllables as more or less information-dense. Again, the actual paper in Language might explain this, but the Time Science article didn't touch on it at all. Since "information density" must be a somewhat subjective semantic classification, and the study's conclusion hinges on such a classification, I'd be quite curious to learn what exactly the parameters were.

What do you guys think? Any other questions/doubts?
If anyone can find a freely accessible version of the actual paper, let me know and I will post it!

Happy Thanksgiving!

Hannah