Processed foods are blamed for many things. But this week, a group of linguists brought it to a whole new level.
To put it bluntly, they claim that the invention of processed foods like yogurt and baby food, thousands of years ago, gave us the word F. A lot of words F. To be more precise, the researchers believe that softer foods have led to more frequent use of "f" and "v" sounds in human languages. (Other language experts are skeptical, we'll talk about it later).
According to the new theory, food influenced language through a complex chain of events.
First came the agriculture and the first forms of food processing such as fermentation, offering easier meals to chew. It was no longer the humans who relied so hard on meat, roots and resistant berries. And as a result, newly pampered humans have ended up with a different type of bite. Their teeth were no longer consumed so much, and they retained more than the natural overbite with which they were born, with the teeth of the upper jaw overlapping the lower teeth.
This physical arrangement of the teeth, in turn, has made it easier for people to do "labicental fricatives" such as "f" and "v", which require the upper teeth to press against the lower lip.
"This change of bite has paved the way for labiodentals in spoken languages," says Damián Blasi, a linguist at the University of Zurich. He spoke during a teleconference with journalists organized by the magazine Science who published the new research.
According to Blasi, humans with an overbite were more likely, by pure chance, to do "f" and "v" sound. Then the normal processes of language evolution took over. Sometimes these language shifts have taken hold and have become a standard part of human languages. "This does not mean that labiodentals will emerge in all languages," says Steven Moran, another linguist at the University of Zurich involved in the research. "It means that the probability of producing labiodentals increases slightly over time."
Scientists have been collecting evidence for their theory for the past five years. It wasn't easy. "The biggest obstacle was, in a nutshell, that linguistic behavior could not be fossilized," says Blasi. There are no audio recordings of conversations in the kitchens of ancient Mesopotamia.
However, they found evidence to support every step in their hypothetical chain of events. There is evidence, for example, that hunter-gatherers have lost their overbite. Computer simulations of the human jaw indicate that it takes more muscular effort to make "f" and "w" have no overbite, so it is obvious that hunters would not be prone to produce those sounds.
Researchers have examined the evolution of the Indo-European family of languages. Generations of linguists have tried to reconstruct ancient versions of these languages, and in fact "we have discovered that, for these groups of languages, it is very likely that the labiodentals have emerged not long before the Bronze Age, in parallel with  development of new food processing techniques, "says Blasi.
Linguists have also discovered that labiodental sounds are less common in the languages of contemporary hunter-gatherer communities in Greenland, Southern Africa and Australia. Where sounds exist, they are sometimes found mainly in words borrowed from other languages.
By putting everything together, the researchers are confident in their theory, and think that this study of the "f" and "v" sounds could change the whole field of linguistics.
According to Balthasar Bickel of the University of Zurich, another coauthor of the study, language is usually considered a purely cultural phenomenon. "If you think about it, however, it's a bit weird," he says. "We produce it with our bodies, especially with our mouths, but as in the case of sign language, even with our hands and other gestures". It is logical, he argues, that biology influences language.
Other linguists are intrigued, but less convinced. "I think the individual pieces seem reasonable," says Alan Yu, a linguist at the University of Chicago. But the whole story strikes him as a speculation. "There are just too many gaps for me to think that this is a real connection" between dietary changes and language, he says. The researchers have not looked at the languages of the hunter-gatherers of the Americas, he says, some of which use labiodental sounds that do not come from European languages.
Salikoko Mufwene, also at the University of Chicago, expressed his doubts. He wrote in an e-mail to NPR that human language had flourished for thousands of years before the advent of agriculture and softer foods, "so it's surprising that people have waited until so late before to produce labio-dental fricificates ".
The anthropologist Shara Bailey of New York University, on the other hand, found the new study that stimulated thought. "I like it!" she says. "It makes me think of something I hadn't thought of."
Bailey's research focuses on the development of the human jaw. "I can really get my students going and maybe test some of these hypotheses by looking at fossil hominids or looking at hunter-gatherers. When you inspire other people to follow and conduct their experiments, I think it's a good thing!"