In a 1986 experiment, expectant mothers read the same passage of The Cat in the Hat aloud twice a day for the last six weeks of pregnancy. After birth, their babies changed their sucking pattern to hear that story rather than an unfamiliar one, even when another woman read it. Learning the sounds of speech starts before the first cry.
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.