The French word for gift, 'cadeau', comes from Old Provençal 'capdel', a chief, the one at the head, from Latin 'capitellum'. In the 15th century, a 'cadeau' was a large ornate capital letter in manuscripts. The meaning then drifted to a needless embellishment, then to a party or entertainment laid on for someone. Only in the classical age did it come to mean a present. A free flourish became a free gift.
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.