New noises linked to soft food
Research suggests dietary changes may have allowed human speech to advance.
The standing theory has been that the range of human sounds has been fairly fixed throughout human history, but a new study reports that sounds such as “f” and “v”, both common in many modern languages, are a relatively recent development.
In fact, they say the development may have been brought about by diet-induced changes in the human bite.
Human speech is incredibly diverse, from ubiquitous sounds like “m” and “a” appearing in virtually all languages, to the rare click consonants in some languages of Southern Africa.
This range of sounds has generally been thought to have come about with the emergence of Homo sapiens around 300,000 years ago.
In 1985, linguist Charles Hockett observed that languages with sounds like “f” and “v” are often found in societies with access to softer foods.
Inspired by this, researchers at the University of Zurich undertook a detailed interdisciplinary investigation of how speech sounds were shaped by changes in human bite as diet changed, particularly as humans transitioned away from hunting and gathering.
Using detailed biomechanical simulations of different human orofacial structures, the researchers showed that a shift in adult tooth structure kept adult’s upper teeth slightly more in front as compared to the lower teeth.
This shift was correlated with the rise of food processing technology such as industrial milling, and may have led to the rise of a new class of speech sounds.
This class of sounds, now found in half of the world’s languages, is known as labiodentals – or sounds made by touching the lower lip to the upper teeth, for example when pronouncing the letter “f”.
Use of labiodentals increased dramatically only in recent millennia, the authors say, following the development of agriculture.
The researchers say their findings suggest language is shaped by culturally-induced changes in human biology to an unrecognised extent.