Think of 'a', 'the', 'and' or 'I': the words we use most are almost always short. This is Zipf's 'law of abbreviation', and it holds in every language studied. Popular words also get worn down over time: 'omnibus' became 'bus'. Researchers have even spotted the pattern in some animal vocalisations, including those of certain primates.
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.