We’re Beginning to Understand Bonobo Speech—And Its Syntax Is Surprisingly Human

In the forests of the Democratic Republic of Congo, a group of bonobos has been doing something that shows striking similarities to human communication: combining vocal calls in structured ways that appear to shift in meaning depending on how they’re used. A new study published in Science has found that these great apes aren’t stringing sounds together at random, but are using combinations where the order and pairing matter. That structure, researchers say, resembles something that humans use all the time—syntax.

This doesn’t mean bonobos have a language in the way humans do. They’re not telling stories, debating ideas, or composing poems. But their vocal combinations appear to be meaningful, and in some cases, the meaning of the combined call is different from what each sound would mean on its own. That’s a big deal, because until now, most scientists thought this kind of communication—called “nontrivial compositionality”—was something only humans did.

To break it down: compositionality refers to how we combine words to make new meanings. For instance, the phrase “bad dancer” doesn’t just tell you two things about someone—it creates a specific concept that’s different from either “bad” or “dancer” on its own. The study found that bonobos do something similar with their calls. Out of several combinations studied, three showed this type of structure where one sound alters the meaning of the other, creating something new.

Researchers recorded 700 vocalizations from wild bonobos and analyzed them using methods borrowed from the study of human language. They looked at the context in which the calls were made—what the bonobo was doing, who was nearby, what was happening in the environment—and then mapped those patterns to understand what the calls might mean. This approach helped them see which calls were used together and how those combinations appeared to shift depending on the situation.

One of the combinations they analyzed included a sound that roughly means “I’d like to…” paired with another that seems to mean “stay together.” When bonobos used this pair, it was often during tense social situations like mating, and the combined meaning may be something like “let’s cooperate” or “stick with me.” In another pairing, a call associated with attracting attention was combined with one that signaled high emotional arousal. That combo may be used to say something along the lines of “look at me, something’s going on here.”

What’s especially interesting is that these aren’t just repetitions of the same calls or random combinations. The meaning seems to shift based on how the calls are ordered and combined—much like how a sentence in human language can change completely if you rearrange the words.

Of course, bonobo communication doesn’t have all the elements of language. They don’t use words to talk about things that aren’t in front of them, and they don’t build endless sentences with complex grammar. But this kind of vocal structure suggests they may share more communication traits with humans than we used to think.

The researchers also point out that their method—looking at how meaning can be inferred from behavior and context—might help us learn more about other animals’ communication too. It’s possible that some species seem less expressive simply because we haven’t been able to interpret their signals with enough detail.

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It’s worth noting that the bonobos in the study weren’t trained or interacting with humans to produce these sounds. These were entirely wild animals communicating with each other as they normally do. That makes the findings even more striking, as they reflect natural behavior rather than learned responses in a lab.

In short, this research doesn’t say that bonobos “speak” in the way humans do. But it does suggest that they can combine sounds in a way that creates new meanings—a skill that, until recently, many thought was unique to humans. It adds to the growing body of work that questions where exactly the line between human and animal communication lies, and how far back in our evolutionary history the roots of language might reach. This shift in thinking is echoed by other recent findings, such as research showing that crows are capable of recursion (a complex cognitive ability once believed to be limited to humans and a few other primates), or, perhaps even more surprisingly, that elephants call each other by names.

Sources: 1, 2, 3