What’s in a somersault? A flap of the lip, a spit of water in the face? More than meets the eye, it seems. They may all be new ways of communicating orangutans have come up with in captivity. The findings suggest such gestural creativity may be ancestral in the hominid line, adding a new piece to the puzzle of language evolution.

Using new expressions to convey meanings for things – known as productivity – is one of the fundamental building blocks of complex language , and it is rarely …