The scientists investigated the rhythm of chimpanzee lip-smacks produced by individuals while they groom another and found that chimpanzees produce lip-smacks at an average speech-like rhythm of 4.15 Hz.
The findings show there has most likely been a continuous path in the evolution of primate mouth signals with a 5Hz rhythm.
African great apes, the closest species to humans, had never been studied for the rhythm of their communication signals.
Dr Adriano Lameira, from the Department of Psychology at the University of Warwick said: “Our results prove that spoken language was pulled together within our ancestral lineage using “ingredients” that were already available and in use by other primates and hominids.
“This dispels much of the scientific enigma that language evolution has represented so far. We can also be reassured that our ignorance has been partly a consequence of our huge underestimation of the vocal and cognitive capacities of our great ape cousins.
“We found pronounced differences in rhythm between chimpanzee populations, suggesting that these are not the automatic and stereotypical signals so often attributed to our ape cousins.
“Instead, just like in humans, we should start seriously considering that individual differences, social conventions and environmental factors may play a role in how chimpanzees engage “in conversation” with one another.
“If we continue searching, new clues will certainly unveil themselves. Now it’s a matter of mastering the political and societal power to preserve these precious populations in the wild and continue enabling scientists to look further.”