In Aymara, spoken by more than one and a half million people in Bolivia, Peru and Chile, the word 'nayra', meaning eye or front, also refers to the past, while 'qhipa', behind, refers to the future. In a study published in 2006, researchers analysed filmed interviews: speakers gestured forward when talking about long ago and pointed behind them for tomorrow. The logic: the past is known and lies before your eyes; the unseen future is at your back.
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.