The speakers of some languages have a reputation for talking quickly while others have a reputation for talking slowly. Is this because some cultures actually communicate quicker than others, or are they just using more words to communicate the same information?

That is what Coupé et al. aims to answer empirically, using a dataset of 17 languages. They conclude that, indeed, the information communicated per second of speech is similar across languages – in particular, around 39 bits/s.

If you’re wondering how a syllable could have a bit value, you have a fun afternoon ahead of you reading about information theory. In an information-dense 8 bit/syllable language like Vietnamese, you on average have a 1 in 256 chance of predicting the next syllable, while in a 5 bit/syllable language like Japanese, you have a 1 in 32 chance. So, there are two competing strategies that balance each other out: either have information-dense syllables, and speak more slowly, or have information-sparse syllables, and speak quicker. Cool!

I couldn’t find anything on whether the same thing is true of dialects. Speakers with some accents speak much more quickly than others – for instance, Northerners are known for speaking quicker than Southerners in the US. This would be a great secondary school or undergraduate summer project. And it wouldn’t even be that hard to run – you could just give people the same piece of text to “translate” into their dialect, then see if the same information is communicated in the same amount of time.

Can a language benefit its speakers in general?

Researching speech efficiency got me wondering: are there specific benefits that speaking a certain language can give you?

I’m somewhat biased against this being true. If speaking East Whereverese raised your IQ by 5 points, you’d expect its beneficial features to be adopted by other languages, or be independently converged upon by multiple languages.

In Outliers, Malcolm Gladwell suggests that one of the reasons why Chinese students perform so well on mathematics tests is because of beneficial features of the Chinese language itself: namely, saying words in English is clunky and takes a lot of syllables, but numbers in Chinese are quicker and easier to speak. Being able to hold numbers in working memory for even a fraction of a second longer can be a real boon for maths ability. By age 4, Chinese children can already count to 40, while Americans of the same age can only count to 15, putting them a full year behind. And this is before formal education starts, so you can’t pin this one on the education system.

Again, this is mysterious to me. If you can upgrade your children’s numerical reasoning by a full year just by giving them a vocabulary that makes it easier to talk about words, why haven’t other languages evolved to do the same thing? I’ve always thought those parents that teach fake languages to their kids were wasting their time, but if Klingon is anywhere near as efficient in talking about numbers as Chinese, maybe they have a point! Are there other cognitive capabilities that the English language enhances that compensate for the mathematical disadvantage it puts its speakers at?

(Note: Scott Alexander points out how Chinese mathematics test scores are kind of fake, in that China struck a deal whereby it only administer the PISA exam (the standard test for comparing countries’ mathematics ability) in its most educated provinces (!). If the US were allowed to do the same thing, you find that the Chinese mathematical advantage goes away. But this wouldn’t explain Chinese kids being able to count higher. So, all in all, not sure what to make of this.)

Appendix: Podcast listening speed

It still boggles my mind that not everyone has realised that you can listen to podcasts and audiobooks at >160% speed while losing no comprehension. This seems to imply that the rate-limiting part of speech – and therefore why languages communicate at the same rate – is how fast people can speak, not how fast people can listen. In which case, I await the day where I can have a neural implant that allows people to communicate all the same information to me in half the time 🙂