Mind & Body

No Matter How Fast Languages Are Spoken, They All Transmit Information at the Same Rate

Walk through an international airport terminal and you're bound to hear all sorts of languages being spoken. Of all of their differences — in tone quality, pitch, and even consonant use — the one that sticks out the most is speed. Some like Spanish, Japanese, and Italian seem to speed along like a drumroll, while others, like Vietnamese or French, seem to roll off the tongue at a more leisurely pace. Regardless of these contrasts, new research published in Science Advances found that one key element is the same across the board: The amount of information transmitted through speech is standard regardless of how fast the language tends to be spoken.

Motormouths, Start Your Engines

The international team of scientists first had to standardize their measure for how much information was packed into each syllable. They decided to measure verbal information in "bits," the same unit used for information transmitted by a cell phone or computer.

The team looked at the same written texts translated into 17 different languages, including English, Italian, Japanese, and Vietnamese, and found that languages that had more syllables also generally conveyed more bits per syllable. For example, Japanese only has 643 syllables and transmits about five bits of information per syllable whereas English, with 6,949 syllables, transmits closer to seven bits of information per syllable. Vietnamese, which relies on a system of tones that affect the meaning of a word, was the most densely packed with eight bits of information per syllable.

Next, the scientists needed to assess the speed of each spoken language. The researchers recruited and recorded 10 speakers, five men and five women, to read 15 written passages in their native tongue. The team's recordings covered 14 of the 17 languages included in the study; they relied on existing recordings for the other three. The investigators noted how long it took each participant to finish their readings and then compared the speed of each language by averaging how many syllables were spoken per second.

Finally, the team determined the rate at which information is transmitted in each individual language by multiplying the language's average speed by the number of bits in each syllable. Their findings are surprisingly consistent: No matter how quickly words rolled off the speakers' tongues, and despite complicated linguistic systems like the tones of Vietnamese, speakers in all 17 languages transmitted information at the same rate: about 39 bits of information per second.

By comparison, Science Magazine reports that only about half that much information is transmitted using Morse code. But computers have us beat in this department: The world's first computer modem, released in 1959, transferred 110 bits of information per second; modern computers are even faster, sending 100 megabits — or 100 million bits — per second.

Of course, there are speed variations among speakers of the same language, too. In English, at least, teen girls tend to speak faster than average while older people may require more time to compose their sentences. The scientists say that their findings held true when accounting for these linguistic differences and were also reflective of "actual phenomena found in more natural settings" beyond the readings they recorded with their participants.

Brain Buffering

The reason why this rate is so consistent across languages is likely due to our brain's limitations. Our brains can only absorb or produce a certain amount of information at any given time; a pair of neuroscientists recently determined that our brains could only process up to nine syllables of English per second. Interestingly, their findings are consistent with the principle known as Miller's law, which says that our short-term memory can only hold seven items at a time (plus or minus two, which is how you get nine).

Bart de Boer, an evolutionary linguist who studies speech production at the Free University of Brussels, told Science Magazine that he agrees our brains are the bottleneck, but that the limitation has less to do with information intake than output. He pointed out that people have no problems with comprehension even when listening to recordings sped up by up to 120 percent.

"It really seems that the bottleneck is in putting the ideas together," he told Science.

Despite our cultural and linguistic differences, at the end of the day, we're all humans whose brains work the same way.

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Discover how language evolved in "The Unfolding of Language: An Evolutionary Tour of Mankind's Greatest Invention" by Guy Deutscher. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Steffie Drucker September 30, 2019

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