An Oxford philologist specialising in Old English, J.R.R. Tolkien had been inventing languages since his teens. He explained that his stories were made to give his languages a world to live in, not the other way round. Quenya, the tongue of the High Elves, draws on Finnish, which he discovered with delight as a student; Sindarin borrows the sounds of Welsh. The Lord of the Rings is, in a sense, the setting for a linguistic project.
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.