The Speed of Languages

It is an almost universal truth that any language you don’t understand sounds like they are being spoken at 200 miles per hour — a storm of alien syllables almost impossible to tease apart.

That, we tell ourselves, is simply because the words make no sense to us. Surely our spoken English sounds just as fast to a native speaker of Urdu. And yet it’s equally true that some languages seem to zip by faster than others. Spanish sounds a lot faster than French; Japanese leaves German far behind — or at least that’s how they sound.

Spectrograms of the syllables

Spectograms of syllables

Is this really true, and if so, how could that be? To investigate this puzzle, researchers from the University of 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 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 counted all of the syllables in each of the recordings and further analysed how much meaning was packed into each of those syllables. A single-syllable word like bliss, for example, is rich with meaning — signifying not ordinary happiness but a particularly serene and rapturous kind. The single-syllable word to is less information-dense. And a single syllable like the short i sound, as in the word jubilee, has no independent meaning at all.

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.

For all of the other languages, the researchers discovered, the more data-dense the average syllable were, 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, but was slowest at 5.18 syllables per second.
  • Spanish, with a low-density .63, ripped along at a syllable-per-second velocity of 7.82.
  • However, the speediest language in terms of syllable speed was Japanese, which edged past Spanish at 7.84, thanks to its low density of .49.

Despite those differences, at the end of a minute of speech, all of the languages would have conveyed more or less identical amounts of information.

“A trade-off is operating between a syllable-based average information density and the rate of transmission of syllables,” the researchers at Lyon wrote. “A dense language will make use of fewer speech chunks than a sparser language for a given amount of semantic information.”

In other words, your ears aren’t deceiving you: Spaniards really do sprint and Chinese really do stroll, but they will tell you the same story in the same span of time.

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