The Speed of a Language

by Kartik Chaturvedi

January 12, 2020
The Speed of a Language image

If you have ever listened closely to different languages, you must have noticed that some are spoken faster than others. Is that just how they are designed, or do faster languages also convey information faster?

Surprisingly, regardless of speed, different languages convey a similar amount of information — about 39 bits per second. Researchers define a bit in linguistic terms as the amount of information that reduces uncertainty by half. Since linguistics information is usually calculated per syllable, this means that if a syllable contains enough information to halve the uncertainty of what is being talked about, that syllable is one bit of information.

Some languages are more efficient at packing information together like gender and tense, and therefore move more slowly to make up for the density. Other languages spread that information out more loosely, and are able to travel at a much faster rate.

So if a language has a low information density, or bits-per syllable, it will take more syllables to express a certain thought. At the same time, since each syllable contains less information, information is spread out over more syllables, and the faster the language can be spoken.

But why only 39 bits? The limiting factor is in processing our thoughts and converting them into sounds with proper grammar, tone, and vocabulary. That’s why listening to fast speech is not very difficult (we can listen to podcasts or YouTube videos at 2x speeds with little problem), but it is impossible to ever talk that fast ourselves.

Of course, the study mentioned above represents just a drop in the vast ocean of our linguistic knowledge, most of which is concentrated to European languages. With more than 6,000 known languages and thousands more dialects in the world, there is a lot of work to be done to better understand how we communicate, and how our languages developed and evolved.

Just for fun, let’s estimate the amount of time it would take to orally convey all of the details of a 3MB photo taken on the average smartphone. At a rate of 39 bits per second, it would take a human (regardless of language), 7 days and nights (168 hours in total) of non-stop speaking to communicate information about each pixel, hues, contrast, focus, and other data about that photo. I guess that gives a new meaning to the saying, a picture is worth a thousand words.

"The most important things are the hardest to say, because words diminish them."

~ Stephen King

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