French fries, volcanic vent, flourishing flower, vector video — you might not be able to pronounce these phrases if not for ancient farmers who unknowingly helped humans develop the ability to enunciate f and v sounds.

In a study published recently in the peer-reviewed journal Science, a team of linguists explored the correlation between human speech and early farming. They built on the 1985 study of American linguist Charles F. Hockett, who observed that languages that include the letter F and V are often used in societies that eat softer food.

How We Eat Shapes How We Speak

In the Paleolithic period, humans had to put force on their jaw bone and molars to bite a tough piece of meat. Over time, their lower jaw grew larger and their molars erupted farther and drifted forward, causing the upper and lower teeth to align whenever they bite. This bite is also known as the edge-to-edge bite.

The edge-to-edge bite, however, changed with the development of agricultural practices. Innately, humans have a slight overbite, which typically disappears during adulthood. This overbite isn’t that case of malocclusion we know, where the upper front teeth extend way over the lower front teeth, prompting teenagers and adults to get orthodontic treatments, such as braces and retainers. In the Paleolithic period, according to the study, the natural slight overbite disappeared far quicker among teenagers because of their hard diet of tough meats. But when humans began to farm and switched to softer plant-based food, they started retaining their slight overbite.

Eating vegetables and fruits doesn’t require the edge-to-edge bite. Chomping into an apple, for instance, involves your top teeth making the first contact, then the bottom teeth pulling the sweet bite into your mouth. This action requires you to have a slight overbite, which, apparently, also helps you to produce F and V sounds.

F and V sounds, also known as labiodentals, are speech sounds produced by positioning the lower lip against the upper teeth. This action won’t be possible if you have not retained your slight overbite. The team of linguists involved in the Science-published study confirmed this.

F and V Sounds — And That Overbite

smiling girl with bracesThe linguists made two sets of biochemical models: one with teeth and jaws that could only do edge-to-edge bite, and another with a slight overbite. Through a series of tests, they found that producing labiodental sounds incur around 30 percent less muscular effort in models with overbite than those with edge-to-edge bite configuration. The tests showed it’s much easier to produce F and V sounds if you have a slight overbite.

The human ability to pronounce “french fries” and “volcanic vent” easily is a fortunate accident, thanks to the rise of farming and the plant-based food diet. The linguists suggested that this development might have led to the evolution of many languages. Nearly half of the world’s languages today include labiodental sounds, after all.

Other researchers, however, noted that the linguists didn’t take the genetic approach to look for signs of positive selection in people who can easily produce the F and V sounds. Nevertheless, this recent study on labiodentals sets off a new conversation that may help shed light on how human languages evolved.