According to a surprising new study, humans could not always easily produce the "f" and "v" sounds. The reason we can now appreciate words like "taste" and "effervescent", the researchers say, has to do with changes in the ancestral human diet and the introduction of soft foods, a development that has altered the way in which we bite and, consequently, the way we talk.
Human language involves all sorts of bizarre noises, from the ubiquitous "m" and "a" sounds found in virtually all languages to the rare consonant clicks expressed in some South African dialects. Anthropologists and linguists have traditionally assumed that the inventory of all the possible vocal sounds used by humans has remained unchanged since our species emerged about 300,000 years ago, but new research published today in Science is challenging this hypothesis for a long time time.
An interdisciplinary research group led by Damian Blasi of the University of Zurich states that the sounds "f" and "v" have only recently been introduced into the human lexicon, emerging as a side effect of the revolution farm. These sounds, which are now present in the vast majority of all human languages, are what linguists call labiodental consonants – sounds produced by pressing the upper teeth on our lower lip.
Here is the story, as presented in the new study: Around 8000 years ago, when humans went from the predominantly carnivorous lifestyle to agriculture, the foods our ancestors ate became softer, with a pronounced effect on human bite. Instead of the marginal bite exhibited by hunter-gatherers, who had to tear hard meat, the agricultural humans retained the juvenile bite that usually disappears in adulthood. With the upper teeth slightly in front of the lower teeth, it has become much easier to make labiodental sounds. Gradually, and by chance, these sounds were integrated into words, which eventually spread in time and space, particularly in the last 2500 years.
At least, this is the theory, even if the new article presents some convincing evidence to support the complaint.
The work is intriguing because it suggests that the human sounds used in language have been more dynamic in history than is conventionally supposed and that certain aspects of language can be traced to relatively recent changes in human biology.
The roots of this study go back to 1985, when the American linguist Charles Hockett demonstrated that words with labiodental sounds were overwhelmingly absent in the languages of hunter societies – gatherers – an observation that attributed to the configuration of the marginal bite due to the absence of soft agricultural lands. Hockett's contemporaries did not buy this subject, but now, almost 35 years later, Blasi and his colleagues have rekindled this idea.
In a press conference held on Tuesday, Blasi said the new study is the culmination of five years of work, with contributions from experts in anthropology, phonetics and historical linguistics. The team, which included researchers from the Max Planck Institute, University of Lyon and Nanyang Technological University in Singapore, devised new research-specific methodologies, including the development of new data sets and models to simulate human biomechanics .
Critics of Hockett's hypothesis argued that wear and tear cannot completely explain the changes in a person's bite pattern, and that edge-to-edge bites did not begin to fade to long after the introduction of agriculture. Writing in the new study, however, the authors admitted that Hockett, who died in 2000, could have been on something, stating that "recent anthropological evidence has shown that tooth wear … is really the main mechanism of post-adolescent bite change, and that, despite considerable variations, there has been a general decrease in edge-to-edge bite since the Neolithic. "
In fact, foods introduced from agricultural products such as porridge, soups and gruel and dairy products such as cheese, milk and yoghurt have led to radically softer diets. It is important to point out that, as the authors pointed out in the study, it was the absence of hard and harsh foods, not the presence of soft foods, which contributed to changes in the configuration of the bite, a physiological process known as occlusion of friction.
A key point of the new research is that an overbite makes it easier to state the labiodentals. This ease of effort, the authors argued, eventually led to the emergence and spread of words with "f" and "v" sounds. The biomechanical computer models used in the study seemed to state this conjecture, showing that 29% less energy is needed to produce labiodentals with an overbite compared to a bite from edge to edge. Speaking at the press conference, the authors stated that the advent of labiodental sounds was not the result of a "deterministic" process, ie it was not inevitable. The adoption of a softer diet simply increased the likelihood of this happening.
"Producing labiodental sounds does not cost to make other sounds," Balthasar Bickel, a linguist at the University of Zurich and coauthor of the study, said at the press conference. "Thousands and thousands of tests" -i.e. the inadvertent introduction of the labiodentals into speech – "for many generations left a statistical footprint", he said – the imprint is the current prevalence of words with labiodentals.
The authors also investigated the languages of the world, discovering that "on average, hunter-gatherer societies have only about 27% of the number of labiodentals exhibited by food-producing societies", as observed in the study. Borrowing from evolutionary biology, the researchers also performed a phylogenetic analysis, but instead of tracking physical changes to species, they monitored changes in Indo-European languages over time. The analysis showed that labiodental sounds spread rapidly in other languages.
"In Europe, our data suggest that the use of labiodentals has increased dramatically only in the last two millennia, correlating with the increase in food processing technology such as industrial milling," Steven Moran, a linguist at the University of Zurich and a co-author of the new study, he said in a press release.
"This study will come as a surprise to many linguistic and linguistic change experts – it certainly surprised me."
It is important to note that the authors did not consider changes in brain development or changes in nutrition that may have influenced this process. As Blasi said at the press conference, "We are not making claims about the brain – we were only testing biomechanical factors."
"This study will come as a surprise to many linguistic and linguistic change experts – it surely surprised me" Tecumseh Fitch, bioacoustics and language evolution expert and professor of cognitive biology at the University of Vienna, told Gizmodo . "The study is an interdisciplinary tour-de-force, combining biomechanical, bioacoustic, comparative and historical methods to give new life to an old hypothesis: changes in the structure of the mouth caused by dietary changes have shaped the historical change of the language."  Fitch stated that the authors have relied on "various assumptions and reconstructions" of unknown factors, in particular biting structures of present and ancient populations, but in the end he believes he has presented "a very plausible case that will open the doors to future detailed research ". which added: "It is probably the most convincing study, but it shows how biological constraints on language change could change over time due to cultural changes."
Ian Maddieson, a linguist at the University of New Mexico, said "this document is a welcome addition to the discussion on the extent to which external linguistic factors influence the phonetic design of human languages." had some reservations about the new research.
In particular, Maddieson was concerned about how the authors categorized and counted certain labiodentals, saying that there was a lack of consensus regarding the interpretation of the data used in the study and that some of the labiodental sounds may have been counted.  Indeed, given the novelty of the study and its rather surprising conclusion, it would be a good idea for other researchers to dive in and explore this possibility further. Regardless, this article has revitalized a hypothesis proposed for the first time about 35 years ago, with authors showing that it is a topic worthy of consideration.
So the next time you shout the word "f" cathartically, make sure you offer thanks to your pioneering ancestors.