Published: Sat, March 16, 2019
Research | By Raquel Erickson

Softer Foods Have Changed How We Talk

Softer Foods Have Changed How We Talk

Changes in human diet resulted in the development of sounds such as "f" and "v", new research suggests. This doesn't account for the wide range of "a" or "m" sounds, or even the clicking associated with some South African languages.

"The set of speech sounds we use has not necessarily remained stable since the emergence of our species, but rather the vast diversity of speech sounds that we find today is the product of a complex interplay of factors involving biological change and cultural evolution", said University of Zurich team member Steven Moran.

Through efforts including detailed biomechanical simulations of different human orofacial structures, Blasi and colleagues showed that a shift in adult tooth structure that kept adult's upper teeth slightly more in front as compared to the lower teeth - a shift that correlated with the rise of food processing technology such as industrial milling - led to the rise of a new class of speech sounds.

Human speech involves thousands of different sounds. They also found that labiodental sounds occurred accidentally when trying to make other speech sounds in the overbite model.

In 1985, Hockett proposed that hunter-gatherers would have had a hard time making "f" and "v" sounds due to their edge-to-edge bite, in which the teeth come together at the front of the mouth and meet evenly.

"Our anatomy actually changed the types of sounds being incorporated into languages", Noreen von Cramon-Taubadel, an evolutionary anthropologist at the University of Buffalo who was not involved in the study, wrote in an email. Such sounds are called the labiodentals, because, to be pronounced, they require both lips and teeth. This is why most scholars believe that biological machinery for producing human speech has remained largely unchanged since humans emerged hundreds of thousands of years ago.


"Before access to softer diets through food processing, the bite would naturally develop into an edge-to-edge bite with age", said Steven Moran, a linguist and co-author at Zurich.

Languages spoken by groups with hunter-gatherer societies in their more recent past are far less likely to use consonants used by longtime farming societies, the study found.

Thousands of years ago, when humans began cooking or preparing their food in other forms, the structure of their teeth altered, and thus, eased the pronunciation of certain letters that are today involved in several worldwide languages, as explained the researchers in their study published Thursday in the Science Magazine.

"Our results shed light on complex causal links between cultural practices, human biology and language", says Balthasar Bickel, project leader and UZH professor.

However, in 1985, Linguist Charles Hockett was the first to think that this may not be true, as letters such as "f" and "v" were not available in indigenous communities that lived on fishing and hunting. They analyzed a database of roughly 2,000 languages - more than a quarter of languages in existence today - to identify which sounds were more and less frequently used, and where.

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