The word comes from Hindi chāmpo, from chāmpnā, to press or knead. In the early 19th century, Sake Dean Mahomed, an entrepreneur from India, opened baths in Brighton offering 'shampooing', a therapeutic massage. The meaning later slid toward washing hair, and the word spread from English to many other languages.
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.