“Speakers of some languages seem to rattle away at high speed like machine-guns, while other languages sound rather slow and plodding,” wrote linguist Peter Roach in 1998. A few months ago researchers systematically quantified Roach’s observation and offered a surprising explanation. Last year, in an issue of the journal Language, François Pellegrino and his colleagues at the University of Lyon in France published their analysis of the speech of 59 people reading the same 20 texts aloud in seven languages. They found Japanese and Spanish, often described as “fast languages,” clocked the greatest number of syllables per second. The “slowest” language in the set was Mandarin, followed closely by German.
But the story does not end there. The researchers also calculated the information density for the syllables of each language by comparing them with an eighth language, Vietnamese, which served as an arbitrary reference. They found that an average Spanish syllable conveys only a small quantity of information, contributing just a fragment to the overall meaning of a sentence. In contrast, an individual Mandarin syllable contains a much larger quantity of information, possibly because Mandarin syllables include tones. The upshot is that Spanish and Mandarin actually convey information to listeners at about the same rate. The correlation between speech rate and information density held for five out of seven of the languages studied, and the researchers conjectured that, despite the diversity of languages in the world, over time they all deliver a constant rate of information, possibly tuned to the human perceptual system.