From Spanish and Swahili to Finnish and Filipino, over 7,000 languages are spoken across the world today. Humans are unique in that we are the only species known to use language. However, new research suggests we might not be as unusual in this capacity as previously thought.

A paper published in Science Advances describes chimpanzees’ ability to create new meanings by combining calls – a technique not so different from how we combine words to produce sentences. This discovery could have major implications for our understanding of how human language evolved.

“Generating new or combined meanings by combining words is a hallmark of human language, and it is crucial to investigate whether a similar capacity exists in our closest living relatives, chimpanzees and bonobos, in order to decipher the origins of human language,” senior author Catherine Crockfor of Max Planck Institute for Evolutionary Anthropology said in a press release.

What Is Language?

Humans communicate orally by combining a relatively small number of sounds (or phonemes) to make words, which are combined again to create sentences. Key to our ability to create almost infinite sequences of sounds with an equally vast number of meanings is our use of “combinational mechanisms.”

These can be divided into two camps. The first, compositional combinations, is when meaning is derived from the sequence’s composite parts, as in the sentence “the ape goes.” The second, non-compositional combinations, is when meaning is unrelated to the composite parts – think of the idiom “go ape.”

Other animals are known to combine sounds to create new meanings – Campbell’s monkeys, for example, precede alarm calls with the sound “oo” to reduce their urgency. However, their ability to do so is relatively rudimentary and often limited to specific situations, such as a predator encounter.

Read More: Chimps, Like Humans, are Fast Talkers — With Their Hands

The Complex Language of Chimpanzees

In contrast, the calls of chimpanzees appear to be remarkably complex. Analyzing thousands of vocalizations from 53 wild chimps in the Taï National Park, Ivory Coast, researchers identified 12 single call types and 16 two-call combinations. A deeper investigation revealed that chimpanzees modify meaning in four distinct ways, using compositional and non-compositional combinations.

The first adds meaning: if A means “feeding” and B means “resting,” AB means “feeding and resting.” The second clarifies meaning: if A means “feeding or traveling” and B means “aggression,” AB means “travelling.” The third enables chimpanzees to conceive new meanings via non-compositional combinations: if A means “resting” and B means “affiliation,” AB means “nesting.” The fourth and final technique is the ordering effect, in which the sequence of the calls impacts their overall meaning, much like how the order of words affects the meaning of sentences.

“This changes the views of the last century, which considered communication in the great apes to be fixed and linked to emotional states,” Cédric Girard-Buttoz, first author on the study, said in a press release.

The Origin of Human Language

The discovery not only offers a fascinating insight into the lives of these great apes but could help explain the development of human language. The researchers say the complex combinatorial abilities witnessed in chimps may have existed in the common ancestor we share.

“Such a system in nonhuman animals has never been documented and may be transitional between rudimentary systems and open-ended systems like human language,” the study authors write.

The findings reflect recent research analyzing the calls of bonobos, finding that they, too, can combine calls to create new meanings. As Girard-Buttoz points out, this suggests either “there is indeed something special about hominid communication” or “that we have underestimated the complexity of communication in other animals as well.”

Read More: Bonobos Communicate Like Humans, At Least When It Comes to Combining Calls

Article Sources

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Rosie McCall is a freelance writer living in London. She has covered science and health topics for publications, including IFLScience, Newsweek, and Health.