Health Desk: Human speech is thought to have come about relatively recently, within the last 70,000 to 100,000 years.
Because of this, there has been little research into the links between the sounds made by non-human primates and the way we speak.
But a new study has shown baboons can make five of the vowel noises thought unique to humans, meaning the origin of language could stretch back much older than we thought - to 25 million years ago.
Researchers from Grenoble Alpes University in France, along with other colleagues, studied 1,335 spontaneous sounds produced by 15 male and female Guinea baboons.
They found surprising similarities that dates the origin of speech back to our common ancestors, 25 million years ago.
'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 co-author Joel Fagot from the Universit� d�Aix in Marseilles.
The researchers performed an acoustical analysis of the grunts, barks, wahoos, copulation calls, and yaks from baboons.
They found, like people who use several vowels during speech, the non-human primates make five distinct vowel-like sounds.
The researchers analysed 1,335 spontaneous vocalizations produced by 15 male and female Guinea baboons in different social contexts.
They also studied the anatomy of vocal tracts from two baboons that died of natural causes.