The grunts, barks and wahoos of baboons contain distinct vowel-like sounds similar to human speech, suggesting language may have begun to evolve 25 million years ago. After analysing 1,335 spontaneous vocalisations produced by 15 male and female Guinea baboons in different social contexts, researchers from Grenoble Alpes University in France found that baboons produce five sounds that have close similarities with vowel sounds used in human speech.
Humans form each vowel by precisely controlling the tongue’s position in the vocal tract. It was previously thought that the voice box of non-human primates such as baboons was too high in their necks to produce the distinct vowel sounds found in human languages. This would mean language must have originated within the last 70,000-100,000 years. However, the new findings suggest that spoken language may have evolved from capacities already possessed by our last common ancestor with baboons, some 25 million years ago.
By examining the vocal tracts of two baboons that died from natural causes, they also found that baboon tongues have the same muscles as human tongues. This suggests that these monkeys use similar tongue movements to humans to form each of the sounds.
“Similarities between humans and baboons suggest that the vowels of human speech probably evolved from ancient articulatory precursors that were passed on and refined all along the hominid line,” said researcher Joel Fagot.