A persistent legend says Aboriginal people answered 'kangaroo', meaning 'I don't understand', when James Cook's sailors pointed at the animal. In fact, the word was recorded in 1770 from speakers of Guugu Yimithirr, near today's Cooktown, the language famous for using compass directions. In the 1970s, linguist John Haviland, who studied the language, confirmed that 'gangurru' really does name a species of large kangaroo.
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.