In the lush forests of Côte d’Ivoire’s Taï National Park, a grunt followed by a hoot might not just be noise—it might be a sentence. New research reveals that wild chimpanzees combine calls in sophisticated ways that parallel some of the fundamental structures of human language.
The findings suggest that the roots of our own capacity for language may run far deeper than once believed, extending back to a shared ancestor with our closest ape relatives.
The Call of the Jungle
For a long time, scientists have known that chimpanzees, like other primates, use distinct calls to communicate—alarm cries for predators, grunts during feeding, hoots to rally the group. But language seemed uniquely human. This study—led by Cédric Girard-Buttoz of the Max Planck Institute for Evolutionary Anthropology—challenges that notion.
The team spent years recording more than 4,300 vocalizations from 53 wild chimpanzees, tracking what, when, and why they “spoke”.
“Recording chimpanzee vocalisations over several years in their natural environment is essential in order to document their full communicative capabilities,” said Roman Wittig, co-author and director of the Taï Chimpanzee Project. These were not just dramatic “look out, lion!” moments, but the rich soundtrack of daily life—resting, grooming, playing, even building nests for the night.
What emerged was startling: chimpanzees combine their calls. From a base repertoire of 12 distinct call types, they strung together pairs—called “bigrams”—in ways that changed meaning dramatically.
“Our findings suggest a highly generative vocal communication system, unprecedented in the animal kingdom,” Girard-Buttoz said.
Four Ways to Talk Like an Ape
The researchers found that chimpanzees used at least four distinct strategies to expand or alter meaning when combining calls. These strategies mirror some of the building blocks of human language.
- New Meanings from Old Sounds
Some call combinations conveyed entirely new meanings. For instance, a “hoo” (often used during feeding) followed by a “pant” (used in social affiliation) suddenly meant “nesting”—a context in which neither call is typically used on its own. “The meaning of the call combination differs from the meaning of the composing units,” the authors wrote. - Clarifying Ambiguity
Others sharpened meaning. A “panted hoo” used in several contexts, like resting or traveling, became more specific when followed by a “scream.” That scream narrowed the interpretation, hinting at a possible threat or urgency. “Clarification can operate not only on one but on both units within a bigram,” the study found. - Combining Meanings
In some cases, combinations preserved the meaning of both calls. A grunt used during feeding and a hoo used during resting combined to signal “feeding while resting”—much like “eating lunch” does for humans. - Changing the Order, Changing the Meaning
And just like “go ape” and “ape goes” have different meanings in English, chimps seemed to respond differently to the order of calls. A “grunt-hoo” didn’t mean the same thing as a “hoo-grunt.” This is especially intriguing, as ordering effects hint at the roots of syntax—the rules that shape sentence structure in human language.
“Generating new or combined meanings by combining words is a hallmark of human language,” said co-author Catherine Crockford. “It is crucial to investigate whether a similar capacity exists in our closest living relatives, chimpanzees and bonobos.”
Echoes of Language in the Ape Lineage
This isn’t the first time apes have shown linguistic flair. Earlier this year, a different study published in Science reported bonobos combining calls into meaningful phrases. Together, the two studies suggest that our ape relatives may share more than we imagined—and that their common ancestor with humans may already have had the building blocks of language.
That ancestor lived around 6 to 8 million years ago. If these combinatorial skills were already present then, it would mean that the gap between human language and animal communication might not be as vast as once believed. “This changes the views of the last century which considered communication in the great apes to be fixed and linked to emotional states,” Girard-Buttoz explained.
Of course, chimpanzees don’t have grammar or sentences as we know them. But they do exhibit compositionality—using elements that carry meaning independently, then altering or enriching those meanings when combined. That puts them far ahead of most other animals. Until now, the most elaborate examples of compositional communication came from birds like the Japanese tit. But bird calls tend to be rigid and context-specific. Chimpanzees, by contrast, are far more versatile.
The researchers analyzed not just which calls occurred together, but how often, in what situations, and with what possible intent. Using a statistical tool called Euclidean distance, they showed that these combinations weren’t random. The bigrams aligned with distinct contexts—feeding, traveling, affiliating, even building nests—suggesting genuine semantic shifts.
The Bigger Picture
So what does this mean for us?
For one, it blurs the line we often draw between ourselves and the rest of the animal kingdom. “Showing that chimpanzees share some of the fundamental properties of human musical rhythm in their drumming is a really exciting step,” Cat Hobaiter, a primatologist at the University of St. Andrews, referring to a separate study on chimpanzee drumming rhythms, told Cosmo Magazine. That rhythm, combined with linguistic flexibility, hints at a deeper root for our unique communicative powers.
It also opens new avenues of research. If chimpanzees can combine calls into phrases, could they one day be shown to recognize grammatical violations? Could young chimps learn “vocal rules” from their mothers? Might other ‘smart’ animals—dolphins, elephants, or even crows—harbor similar combinatorial systems?
There’s a catch, though. Many of the chimpanzees in this study live in habitats increasingly threatened by human activity. “In order to document their full communicative capabilities is becoming increasingly challenging due to growing human threats to wild chimpanzee populations,” Wittig warned.
Still, this research marks a turning point. It suggests that language-like structures may not be an all-or-nothing phenomenon but a spectrum—one that stretches across species, shaped by the evolutionary pressures of life in social groups.
Chimpanzees may not speak, per se. But they’re saying more than we ever realized.
The findings appeared in the journal Science Advances.
