The Rosetta Stone helped experts learn to read Egyptian hieroglyphs.Credit: Juan Naharro Gimenez/Getty
Humanity might once have spoken many more languages than it does today, with tens of thousands in use between 3,000 and 1,000 years ago. This far exceeds the more than 7,500 unique languages now used worldwide.
The findings, published on 23 July in Science1, suggest that the rise of agriculture spurred an initial language boom as people shifted from a nomadic, hunter-gatherer lifestyle and settled into small, isolated communities. If accurate, these results suggest that language extinction is not a uniquely modern phenomenon, says Heidi Harley, a linguist at the University of Arizona in Tucson.
The true historical diversity of languages suggested by this analysis is “mind-blowing”, she says. “The sheer number of languages that they projected to have existed is like, ‘What? That’s crazy’.”
Lost languages
Aside from written sources, evidence of language in the archaeological record is sparse — meaning that researchers often know “surprisingly little” about historical language diversity, says Joe Salmons, a historical linguist at the University of Wisconsin–Madison.
This has led researchers to propose widely differing accounts of how language diversity has evolved over time. For the most part, those calculations are “back-of-the-envelope figures”, says co-author Claire Bowern, a historical linguist at Yale University in New Haven, Connecticut.
The transition to farming settlements in the Neolithic, like this one in Çayönü, Turkey, helped spur a boom in linguistic diversity.Credit: Omer Yasin Ergin/Anadolu Agency/Getty
In their study, Bowern and her colleagues aimed to track the global trajectory of language diversity over the past 12,000 years. They began by estimating how many languages were spoken 12,000 years ago, which was around the end of the last glacial period. To do so, they divided the approximate total global population at the time by the average size of hunter-gatherer groups from the same ethnic and cultural background. For this model, the researchers worked on the assumption that these groups of around 800 people spoke the same language — an inference based on twentieth-century research of native Alaskan groups and global historical language diversity.
Their calculation suggested that between 3,300 and 7,800 languages were spoken 12,000 years ago.
The team then aimed to estimate how language diversity has evolved over time, using statistical models. Because the structure of many societies changed at the end of the last glacial period, shifting from nomadic hunter-gatherer groups to agricultural communities and expanding into nation states, the model assumed that the groups speaking the same language eventually became larger.
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Despite this, the analysis suggests that language diversity rose over the next few millennia as agriculture become more widespread globally, and peaked around 2,000 years ago, when tens of thousands of languages were in use — about ten times as many as were spoken at the end of the last ice age.
Why this happened is unclear, but Bowern suspects that one factor was the transition from nomadic to more permanent settlements. This is supported by research in New Guinea and Vanuatu, which suggests that the dialects and languages of small farming settlements diverge more starkly from those of their neighbours than do those of hunter-gatherers in the same region.
