Higher pitch, exaggerated melody, short sentences: 'baby talk' shows up in many cultures. A huge 2020 study by 67 labs testing more than 2,000 infants confirmed that babies listen longer to this style than to adult-directed speech. Far from silly, it grabs attention and highlights the sounds of the language.
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.