Human speech sounds evolved because of our diet, study says

A Paleolithic edge-to-edge bite, left, and a modern overbite/overjet bite.

(CNN)Although languages around the world vary greatly, some share similar speech sounds. A new study suggests that labiodental sounds like "f" and "v" are included in about half of the world's languages due to a change in our diet that relies on softer foods.

This contradicts the theory that the range of human sounds has remained unchanged since Homo sapiens emerged 300,000 years ago. The study was inspired by the hypothesis of linguist Charles Hockett, a leading figure in the field to help define linguistics as a science between the 1930s and the 1960s.