One of two shapes is called kiki and the other bouba: a spiky star, or a soft blob like a cloud. You already know which is which. In 1929 the psychologist Wolfgang Köhler asked readers the same thing with two made-up words, takete and maluma, and in 2001 V. S. Ramachandran and Edward Hubbard swapped in kiki and bouba and found that about 95 per cent of people gave the spikes to kiki. A 2022 study of 917 people speaking 25 languages found the same pull almost everywhere.

The tidy explanation was that this is something a mind built for language does: the lips round for bouba, the tongue snaps for kiki, and we hear the shape of our own mouths. Then in February 2026 a team in Padua played the two sounds to chicks less than a day old, chicks that had never heard anyone speak, and the chicks spent more time by the spiky shape when they heard kiki and by the round one when they heard bouba.

So the match may be older than words, older than us, as old as whatever we share with a chicken. I like that. Part of what a word means it brings with it, before anybody has agreed what it means.