In the Middle Ages, the port of Béjaïa in Algeria, known to Europeans as Bougie, exported large quantities of beeswax. Around 1300, French 'bougie' meant this fine wax, and by the late 15th century the candle made from it. The word outlived electricity and even made it under the bonnet: a spark plug in French is a 'bougie d'allumage'.
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.