Endangered apes reveal roots of human language

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Young bonobo
A young bonobo ape, a primate unique to Congo and humankind's closest relative, clings to its mother at Lola Ya Bonobo sanctuary just outside the capital Kinshasa, October 31, 2006. Scientifically named Pan paniscus, but more commonly known as pygmy chimpanzees, bonobos share 98.4% of their genetic make-up with humans and are at risk of extinction due to more than a decade of conflict in Central Africa. Reuters

The goal to find the origin of human language could be cleared in the latest study that explored the roots of primate lineage into our language. Researchers have found that wild bonobos are able to vocalise in a similar manner to human infants that may tell more about the evolution of human speech.

According to a study published in the journal PeerJ, the researchers explored how young bonobos, man’s closest living relatives, does peeping, similar to the burbling of human infants before they form words. Human infants  produce vocalisations in a wide range of emotional states and situations. The researchers said the animals also have vocalisations that are usually made in relatively narrow behavioural contexts linked to emotional states such as to express aggressive motivation or to warn about potential predators.

The ability to make vocalisations in certain emotional states is considered one of the factors required for the development of language, according to researchers. Such vocal flexibility is "an important transition toward what we see in human speech," study leader Zanna Clay, a psychologist at the University of Birmingham in the United Kingdom, said.

Vocal flexibility is already “present in our common ancestor, before humans diverged from the rest of the great apes" about seven to eight million years ago, Clay stated. Bonobos use peeping in several contexts, including eating, communicating danger and resting, possibly related to humans exhibiting  “functional flexibility” when vocalising in a variety of situations.

The type of functional flexibility they observed in bonobos could represent an important evolutionary transition from functionally fixed animal vocalisations towards flexible human vocalisations, which seems to have appeared in the shared common ancestor between humans and great apes, researchers said.

In addition, the study suggests against the current models in human language that  human speech may not be unique among primates in their ability to produce functionally flexible vocalisations. Researchers said the “peep” calls of wild bonobos may represent a somewhat intermediate stage between functionally fixed, as seen in most primate vocalisations, and functionally flexible signals, as seen in most human vocalisations.

However, the findings require more research "on our great ape relatives before we can make conclusions about human uniqueness. The more we look, the more continuity we find among animals and humans," Clay noted.

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