Why are some languages spoken faster than others?

WERE THIS article written in Japanese, it would be longer. A Thai translation, meanwhile, would be shorter. And yet those reading it aloud, in either language or in its original English, would finish at roughly the same time. This peculiar phenomenon is the subject of new research which finds that languages face a trade-off between complexity and speed. Those packed with information are spoken slower, while simpler ones are spoken faster. As a result, most languages are equally efficient at conveying information.

In a study published this month in Science Advances, Christophe Coupé, Yoon Mi Oh, Dan Dediu and François Pellegrino start by quantifying the information density of 17 Eurasian languages, as measured by the ease with which each syllable can be guessed based on the preceding one. Next, they record the rate at which 170 native speakers read 15 texts out loud. Finally, armed with data about the information contained in a piece of text and the speed at which it can be spoken, the authors derive the rate at which information is communicated.