Humans have many strings of sounds to express the concept of apple—pomme, manzana, mela, pingguo. In the Netherlands, a group of nine chimpanzees living in captivity had their own way of communicating apple—one particular intonation of grunt. But when they were moved to Edinburgh Zoo and integrated into a new group of chimps, that changes. The second group of chimpanzees have their own form of grunts, and three years later, as New Scientist reports, the Dutch chimps have been found to adapt the tone, or peak frequencies, of their apple sounds to match that of their Scottish hosts.
It’s an exciting development for some studying chimpanzee communication, because it implies that the primates have the ability to learn different tones for different objects—a kind of bilingualism that only humans were previously thought capable of . Earlier ideas about chimpanzee vocalization assumed that, unlike humans who can easily adapt to new languages, “chimp words for objects are fixed because they result from excited, involuntary outbursts,” Andy Coghlan writes for New Scientist.
“An extraordinary feature of human language is our ability to reference external objects and events with socially learned symbols, or words," said the head researcher on the study, Dr. Katie Slocombe. "These data represent the first evidence of non-human animals actively modifying and socially learning the structure of a meaningful referential vocalization.”
The team gathered their data by recording the chimpanzees before and after they were integrated in Scotland. They chose to focus on the word “apple” because the call for it was found to be the most different between the two groups.
The study inspires new questions about chimp language capabilities in the wild. Slocombe says that it would be advantageous, and therefore would make sense, that wild chimps, who sometimes change social groups during their lifetime, may be able to adapt their vocalizations to new sounds in order to fit in.
However, some of the scientific community is skeptical about the magnitude of these findings. As Brandon Wheeler of the University of Kent in Canterbury, UK, told New Scientist, the discovery does indeed show that communication between chimps is more flexible than we previously thought. But this doesn’t necessarily warrant its comparison with humans’ bilingual capabilities. "Like [human] laughter, chimp food-associated grunts are species-specific calls that vary modestly based on what we might call 'learned' accents, but this is rather different from the fact that the Spanish use the word 'manzana' to refer to what the English call 'apples,'" he says.
Head on over to New Scientist to listen to a recording of the chimpanzee’s change of accent, but be warned: an untrained ear may have difficulty telling a big difference between the grunts.