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Can Apes Speak?

A new demonstration hints that an orangutan might possess one of the building blocks of rudimentary spoken language.

By Nathan Collins


(Photo: David Wynia/Flickr)

While some form of language and communication exists throughout the animal kingdom, the ability to speak is unique to humans, in part because of our vocal chords.According to standard thinking, the vocal chords of chimpanzees, gorillas, and orangutans just aren’t flexible and coordinated enough to learn anything we’d call speech.

As it turns out, that standard thinking may be wrong: Researchers report this week in Nature that they’ve taught an orangutan named Rocky to make a few new sounds, hinting that the foundations of spoken language may have existed before the earliest humans entered the evolutionary scene several million years ago.

In a way, it’s not very surprising that great apes like orangutans should have some basic capacity to learn to make new, speech-like sounds. They can—and do—communicate with sounds, just not with the sophisticated repertoire of sounds that humans possess, or with the apparent ability to learn new sounds. And as our closest living relatives, it’d be surprising if they didn’t have any capacity to learn any human-like speech sounds. Yet past attempts to teach apes new sounds have been unsuccessful.

The foundations of spoken language may have existed before the earliest humans entered the evolutionary scene.

Rocky the orangutan may change that. A group of researchers led by Durham University anthropologist Adriano Lameira first met Rocky when he was three and a half years old, and by that time he was already making unusual sounds they dubbed “wookies.” The question was, did other orangutans make those sounds? And were the noises accidents brought on by excitement, or was Rocky actually in control of them?

To find out, Lameira and his team first compared Rocky’s wookie sounds to a catalogue of orangutan calls, but couldn’t find anything quite like a wookie; the closest sound, called a grumph, was higher-pitched and shorter than a wookie. That meant wookies were novel, but still not necessarily intentional.

To test whether Rocky meant to make the sounds, one researcher made more than 500 low- and high-pitch wookies in front of Rocky, who was free to respond however he liked. But rather than make random sounds or random wookies, a frequency analysis of Rocky’s responses suggests he tried to match his wookie pitch to the researcher’s—when she went high or low, Rocky followed suit.

The study is just a start, really, since it involves only one orangutan with some limited form of vocal control. But, the researchers argue, Rocky’s wookie sounds are a strong hint that, long before humans, apes already had “a crucial prerequisite for the onset of spoken language evolution.”