When you hear a language that you don’t understand, it always sounds like it’s whizzing by you at a million words per minute. People are also generally ignorant of the way they themselves contract colloquialisms and make their natural speech slurred and hurried. This is all natural. But recent research has given some interesting information regarding the speed of several common languages, including which has the most information packed into the fewest amount of syllables, and which language has the most syllables. Where does your language stack up?
…[R]esearchers from the Université de Lyon recruited 59 male and female volunteers who were native speakers of one of seven common languages — English, French, German, Italian, Japanese, Mandarin and Spanish — and one not so common one: Vietnamese. All of them were instructed to read 20 different texts, including the one about the house cat and the locked door, into a recorder. All of the volunteers read all 20 passages in their native languages. Any silences that lasted longer than 150 milliseconds were edited out, but the recordings were left otherwise untouched.
The investigators next counted all of the syllables in each of the recordings and further analyzed how much meaning was packed into each of those syllables. […]
With this raw data in hand, the investigators crunched the numbers together to arrive at two critical values for each language:  the average information density for each of its syllables and  the average number of syllables spoken per second in ordinary speech. Vietnamese was used as a reference language for the other seven, with its syllables (which are considered by linguists to be very information-dense) given an arbitrary value of 1.
Just to be clear, the first measurement basically deals with the semantics. For example, there’s a lot more information packed into the word “cry” than there is in the word “the.” The second measurement is self-explanatory – just how many syllables are used within a second. A language like Mandarin concerns itself more with pitch, as opposed to speed, because the way you say the same syllable can completely change the meaning – therefore, it’s natural for such a language to have a relatively low syllable-per-second ratio. This is indeed what the researchers found.
For all of the other languages, the researchers discovered, the more data-dense the average syllable was, the fewer of those syllables had to be spoken per second — and thus the slower the speech.
English, with a high information density of .91, was spoken at an average rate of 6.19 syllables per second. Mandarin, which topped the density list at .94, was the spoken slowpoke at 5.18 syllables per second. Spanish, with a low-density .63, ripped along at a syllable-per-second velocity of 7.82.
The true speed demon of the group, however, was Japanese, which edged past Spanish at 7.84, thanks to its low density of .49.
The highly inflected language of Japanese makes for low information density, but it certainly ends up with a lot of syllables per second. The following video of a famous comedy duo exemplifies the potential speed of Japanese. But note, before you see it, that Japanese people usually don’t speak this fast – they’re professionals, and they probably clocked in at more like 12 syllables per second (though I haven’t measured).
The authors of the study were intent on emphasizing two particular points about their research.
First, that cross-language research like this may be able to reveal the role of various factors such as syllables, words, and information quantity, with regards to memory span. For example, the authors suggest that if we indeed forget simply because of the passage of time (what memory researchers call “decay”), then the speed of languages might affect how much information people forget. On the other hand, they say, “if linguistic factors matter, one could imagine that differences across languages in terms of syllabic complexity or speech rate would influence memory spans. ”
Second, the authors stress that, basically all languages would be able to communicate the same amount of information, given the same amount of time. They were careful in saying the results don’t suggest that Japanese is “the fastest language.” But, if you come from a language (like English) where syllables are important, it probably will sound like the fastest, unless/until you learn it.
I’ll leave you with one last video that I consider to be an appropriate ode to the world’s languages, in all their equal glory.