expectlabs:

When you hear a language that you don’t speak, it usually sounds like it’s speeding by at an incomprehensible rate. Researchers from the Université de Lyon decided to find out once and for all why certain languages sound so much faster than others. For the study, 59 native speakers of English, French, German, Italian, Japanese, Mandarin, Spanish, and Vietnamese, were instructed to read the following passage out loud in each of their native languages:

“Last night I opened the front door to let the cat out. It was such a beautiful night that I wandered down to the garden to get a breath of fresh air. Then I heard a click as the door closed behind me.”

Two values were calculated for each language: the information density of the average syllable, and the average number of syllables spoken per second. The density was determined by analyzing how much meaning the average syllable contained. For example, a single-syllable word like “love,” has more meaning packed into it than another single-syllable word, like “to.”

The results found that the more data-dense a language’s average syllable was, the fewer those syllables had to be spoken per second, leading to slower speech. Mandarin, which topped the density list at 0.94, was the slowest language in the group, spoken at 5.18 syllables per second. In Mandarin, the way you say a syllable can change the meaning – therefore, it makes sense that a language that is more concerned with pitch over speed to have a lower syllable-per-second ratio. The fastest language in the group was Japanese, which edged past Spanish at 7.84, because of its lower 0.49 density. A language’s speed hinges on the correlation between its information density and the rate of speech. Interestingly enough, while languages do indeed have different “speed limits,” most are able to convey the same amount of information in exactly the same amount of time.