Chimpanzees may actually be capable of speech, study of old footage suggests

Great apes may be able to produce ‘first words’ similar to those spoken by human babies

A new examination of controversial old footage of chimpanzees suggests the apes may be capable of learning to speak human-like words given the right circumstances.

The study, published in the journal Scientific Reports, suggests that chimpanzees likely possess the basic brain building blocks to produce “first words” similar to those spoken by human babies in their babbling stage.

This adds to the notion that great ape vocalisation abilities are underestimated, according to the international team of researchers from the UK, Sweden, and Switzerland.

Scientists have wondered for decades why humans are the only primates to have evolved speech even though some great apes like gorillas and bonobos have learned to communicate via vocal sounds and gestures.

Researchers have speculated this could be due to differences in throat organisation as well as variations within the brain.

Past research has hinted that chimpanzees may be an outlier among apes with the ability to speak human words, albeit at a rudimentary level under special circumstances.

In one study decades ago, a husband–wife duo coaxed their adopted chimp over several years to say simple words like “mama” and “papa”.

The work was discredited, however, because of ethical concerns that the infant chimp was taken away from its mother from the wild.

The new study assessed such documented cases of chimpanzee communication and subjected the recordings to phonetic analysis.

Scientists found three recorded videos suggesting that chimps could be taught to speak human words in a rudimentary way.

In particular, chimpanzees may be capable of utilising their voice, jaw and lips to speak individual syllables.

They may even be capable of achieving a contrast in how they pronounce consonants and vowels, researchers said.

In one of the old videos recorded by the husband and wife team, the adopted chimpanzee can be heard saying “papa” at least three times and the word “cup” once.

Two other videos assessed in the new study, including one shared in 2007 on YouTube, capture chimps uttering the word “mama”.

Spectrogram analysis, from top, of utterances by chimps Johnny and Renata and the word ‘mama’ uttered by one of the study authors (Scientific Reports)

While the chimp vocalisation methods seem different from human speech, researchers said these attempts are “essentially word-like”.

They further conducted an online experiment in which human listeners naive to the origins of the recordings “reliably perceived” the chimpanzee utterances as syllables “ma-ma”.

However, citing a limitation of the study,, researchers said their analysis is based on secondary data, sourced from historical footage.

They called for controlled ethical experiments to validate the findings and investigate the conditions in which chimpanzees may acquire human speech-like vocalisations.

“Great apes can produce human words; the failure to demonstrate this half a century ago was the fault of the researchers, not the animals,” scientists concluded.