A broad range of evidence from linguistics, genetics, paleontology, and archaeology suggests that Neanderthals and Denisovans shared with us something like modern speech and language, according to Dutch psycholinguistics researchers Dr Dan Dediu and Dr Stephen Levinson.

Neanderthals have fascinated both the academic world and the general public ever since their discovery almost 200 years ago. Initially thought to be subhuman brutes incapable of anything but the most primitive of grunts, they were a successful form of humanity inhabiting vast swathes of western Eurasia for several hundreds of millennia, during harsh ages and milder interglacial periods.

Scientists knew that Neanderthals were our closest cousins, sharing a common ancestor with us, probably Homo heidelbergensis, but it was unclear what their cognitive capacities were like, or why modern humans succeeded in replacing them after thousands of years of cohabitation.

Due to new discoveries and the reassessment of older data, but especially to the availability of ancient DNA, researchers have started to realize that Neanderthals’ fate was much more intertwined with ours and that, far from being slow brutes, their cognitive capacities and culture were comparable to ours.

Dr Dediu and Dr Levinson, both from the Max Planck Institute for Psycholinguistics and the Radboud University Nijmegen, reviewed all these strands of literature, and argue that essentially modern language and speech are an ancient feature of our lineage dating back at least to the most recent ancestor we shared with the Neanderthals and the Denisovans. Their interpretation of the intrinsically ambiguous and scant evidence goes against the scenario usually assumed by most language scientists.

The study, reported in the journal Frontiers in Language Sciences, pushes back the origins of modern language by a factor of ten – from the often-cited 50,000 years to 500,000 – 1,000,000 years ago – somewhere between the origins of our genus, Homo, some 1.8 million years ago, and the emergence of Homo heidelbergensis.

This reassessment of the evidence goes against a scenario where a single catastrophic mutation in a single individual would suddenly give rise to language, and suggests that a gradual accumulation of biological and cultural innovations is much more plausible.

Interestingly, given that we know from the archaeological record and recent genetic data that the modern humans spreading out of Africa interacted both genetically and culturally with the Neanderthals and Denisovans, then just as our bodies carry around some of their genes, maybe our languages preserve traces of their languages too.

This would mean that at least some of the observed linguistic diversity is due to these ancient encounters, an idea testable by comparing the structural properties of the African and non-African languages, and by detailed computer simulations of language spread.

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Bibliographic information: Dediu D and Levinson SC. 2013. On the antiquity of language: the reinterpretation of Neanderthal linguistic capacities and its consequences. Front. Psychol. 4: 397; doi: 10.3389/fpsyg.2013.00397