Speech Speed May Vary Between Languages But Information Rate Stays The Same


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English speakers talk faster than Japanese speakers – at an average rate of 11 syllables to one, to be precise. But when it comes to language efficiency (that is, how much information is conveyed in a given period of time), it is all much of a muchness. According to linguists writing in the journal Science Advances, we all transfer information at a rate of 39.15 bits per second – no matter our mother tongue.

The main takeaway from the research is the more efficient the language, the slower the rate of speech. Basque, for example, was rated the least "information-dense" of the 17 Eurasian languages studied at five bits per syllable. (A bit being the amount of information needed to reduce uncertainty by half.) But it was spoken at a relatively high average speed of eight syllables per second.


In comparison, Vietnamese is an information-dense language at eight bits per syllable. However, it is spoken at a slower pace – five syllables per second, on average. In terms of the amount of time it takes to convey a certain amount of information, however, Basque and Vietnamese are the same.

Researchers at the University of Lyon came to this conclusion after calculating the information density of 17 languages from Europe and Asia, including German, English, French, Spanish, Korean, Japanese, and Turkish. The team then compared the languages' information density to the average rate of speech of 10 speakers from each language, who read 15 texts in their native tongue. 

The results suggest that the rate of information remains constant across languages – at about 39.15 bits per second. This stuck regardless of the various stylistic differences between languages. For example, the number of phonemes, which range from 25 in Japanese and Spanish to over 40 in English and Thai.

The study authors conclude that this suggests there is an optimal range when it comes to the rate at which information is conveyed, although there may be variation between individuals. (Interestingly, previous studies have suggested that fast talkers produce less informative content than their more conscientiously spoken peers.) 


But it will be interesting to see if these findings hold up in the study of other languages. The 17 analyzed here are just a tiny fraction of the 7,000 or so languages spoken across the world – and they are geographically limited to Europe and Asia. The researchers also hope to find out if the same rules apply to casual conversation.