Lip-Smacking Primate Call Gives Clues to Origin of Human Speech (Video)

The ability to speak has placed human communication far above any other species'. Complex and intricate, it allows people to be subtle or blunt in the way they interact with others. How this speech evolved, though, has evaded researchers for years. Now, new findings may hint at the origins of our ability to form words and create language.

The study examined the rare gelada, a primate that uses vocal lip-smacks during friendly encounters with one another. Living only in the remote mountains of Ethiopia, these mammals use a speech-like undulating rhythm--a stark contrast to other apes and monkeys that typically use just one or two syllables and lack rapid fluctuations in pitch and volume. Also known as the "gelada baboon," the species is mostly terrestrial, and spends much of its time foraging in grasslands.

Thore Bergman, the lead researcher, first became intrigued by geladas when he began studying them in 2006. "I would find myself frequently looking over my shoulder to see who was talking to me, but it was just the geladas," he said in a press release. "It was unnerving to have primate vocalizations sound so much like human voices."

In order to better study these voices, Bergman analyzed recordings of the geladas' vocalizations, which are known as "wobbles." Because these primates vocalize while lip-smacking, the pattern of sound that they produce is structurally similar to human speech. Both humans and geladas use a form of communication that corresponds to opening and closing parts of the mouth. In fact, Bergman theorizes that it's possible that gelada communication could sometimes have the same function as small talk in humans rather than always sending a direct message.

"Language is not just a great tool for exchanging information; it has a social function," Bergman said in a press release.

He found that structurally, both human speech and gelada vocalizations are structurally similar. This could allow scientists to better understand how human communication first arose, and what led to the eventual formation of language.

The findings are published in the journal Current Biology.

Want to see and hear the geladas in action? Check out the video here.