When people without a shared language come together, they cobble together a pidgin, simple and limited. Children who grow up with it as a first language often turn it into a complete language with real grammar: a creole. Tok Pisin, now an official language of Papua New Guinea, calls a hospital haus sik, the 'sick house'.
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.