In 2016, an international team combed through basic word lists covering nearly two-thirds of the world's languages. They found that certain sounds go with certain meanings far more often than chance would predict. The word for 'nose' often contains an n, 'tongue' an l, and 'small' an i. These links show up in unrelated language families, so neither shared ancestry nor borrowing can explain them.
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.