In 2024, a team analysed hundreds of African elephant rumbles recorded in Kenya. A computer model could guess who each call was meant for, and elephants responded more strongly to calls addressed to them. Unlike dolphins, they don't imitate the recipient's own call: they seem to use an arbitrary label, just as we do.
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.