Neanderthals Had Their Own Language – But Was It Like Ours?

It is widely accepted that the capacity for language-like communication arose before modern humans split off from Neanderthals and Denisovans, suggesting that these now-extinct hominins were probably able to speak. According to the authors of an as yet un-peer-reviewed study, however, the inability of our prehistoric relatives to learn Homo sapiens' languages may have prevented them from ever fully integrating with us, possibly contributing to their eventual demise.

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While the linguistic systems of our Pleistocene ancestors remain unknown, the researchers note that human language is characterized by "ergodicity", which refers to the ability to invent multiple dialects that reflect cultural differences between different groups, but which everyone has the ability to learn. The study authors therefore sought to determine when the capacity for ergodicity first arose and whether Neanderthals might have shared this key attribute.

To do so, they looked for evidence of "polyphilia", which denotes a tendency to diversify local customs in order to create cultural markers of group identity. This, the researchers say, allows human populations to maintain a sense of “us” and “them”, thus creating a distinction between group insiders and outsiders.

Polyphilia can be expressed through multiple behavioral modalities, including artwork, dress, dietary customs, and lifestyles. However, language is a particularly strong carrier of polyphilia, since it’s almost impossible for an adult to become fluent in a foreign tongue with no hint of an outsider accent, all of which renders speech an excellent marker of cultural identity.

Importantly, however, a child can achieve native fluency in any language that they are exposed to, indicating that we all carry an innate capacity to adopt the behaviors, norms, and cultures of any foreign group. 

Examining the available archaeological evidence, the researchers suggest that polyphilia may have first arisen a little under 50,000 years ago, when a lithic industry called the Aurignacian spread through the Homo sapiens populations of Eurasia. Within this species-wide phenomenon, regional differences in ornamental artifacts suggest that material culture may have been used as a marker of group identity.

In contrast, Neanderthal tools and other artifacts display no such variation, implying that our sister lineage may have lacked this capacity for group-specific culture. This conclusion is supported by brain anatomy, with structural differences between the prefrontal cortex of modern humans and Neanderthals hinting at a greater capacity for creativity – and therefore polyphilia – in our own species.

Overall, these findings suggest that ergodicity arose long after Homo sapiens and Neanderthals split, and was probably not shared by both lineages. “One possible consequence was that Neanderthals… were not able to learn sufficiently well any of the languages spoken by contemporary H. sapiens, or far-away Neanderthal groups,” write the researchers. 

“Neanderthals’ likely inability to fully speak like sapiens may have contributed to them being considered out-group strangers, no matter how long they stayed within a sapiens group,” continue the study authors. “This continued 'othering' may have prevented full assimilation within the colonizing groups of H. sapiens, and contributed to selection against hybrids, and ultimately to the Neanderthals’ demise,” they conclude. 

The study is available as a preprint on EcoEvoRxiv.