To the Anglo-Saxons, 'wealh' meant a foreigner, especially a Romanised Celt. The Celts in the west of the island thus became the Welsh, and their land Wales. The same Germanic root lies behind Cornwall, Wallonia in Belgium, Wallachia in Romania… and the walnut, literally the 'foreign nut'. The Welsh, for their part, call themselves Cymry, 'fellow countrymen'.
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.