Japanese and Spanish, often described as “fast languages,” clocked the greatest number of syllables per second. The “slowest” language in the set was Mandarin, followed closely by German. An average Spanish syllable conveys only a small quantity of information, contributing just a fragment to the overall meaning of a sentence. In contrast, an individual Mandarin syllable contains a much larger quantity of information, possibly because Mandarin syllables include tones. The upshot is that Spanish and Mandarin actually convey information to listeners at about the same rate. The correlation between speech rate and information density held for five out of seven of the languages studied, and the researchers conjectured that, despite the diversity of languages in the world, over time they all deliver a constant rate of information, possibly tuned to the human perceptual system.