Some languages sound rapid-fire, others more measured. Yet a 2019 study of 17 languages found they all convey roughly 39 bits of information per second. The trick: fast-spoken languages pack less information into each syllable, while slower ones pack in more. It's as if the human brain sets a shared speed limit for communication.
In Kuşköy, a mountain village in northern Turkey, people talk across valleys by whistling Turkish. A 2015 study showed that whistled Turkish draws on both hemispheres fairly evenly, whereas spoken Turkish relies mostly on the left. The physical form of the signal, it turns out, matters to the brain.
Speech has no gaps between words. In 1996, researchers played 8-month-old babies a continuous stream of made-up syllables for just two minutes. The infants picked out the 'words' by tracking which syllables tend to follow one another. That's probability calculation, done without a calculator or any visible effort.