“Golden Age” of Language Diversity Today's 7,500 Languages Are Survivors of an Ancient Bottleneck

Humanity may have spoken fewer languages before farming than we do today — and tens of thousands more at the height of ancient empires. A new study in Science reconstructs 12,000 years of linguistic history, revealing a surprising "golden age" of language diversity roughly 1,000 to 3,000 years ago, followed by a dramatic collapse that began long before European colonialism.

Today, people speak or sign around 7,500 languages. Yet this figure provides only a snapshot of a constantly changing history. How many languages existed before written records? Did agriculture reduce linguistic diversity by allowing expanding farming populations to replace smaller hunter-gatherer groups? Or did population growth initially create more opportunities for new languages to emerge?

An international research team involving researchers from Spain, the USA and Germany have reconstructed plausible trajectories of global language diversity across the last 12,000 years. Their study, published in Science, suggests that language diversity increased for most of the Holocene, reached a remarkable peak between approximately 1,000 and 3,000 years ago, and then declined rapidly thereafter.

Reconstructing a history without written records

“This paper presents an innovative approach to understanding the dynamics of human cultural diversity in the past, addressing one of the central yet least accessible questions in the human sciences. Progress has been limited not by a lack of theoretical interest but by the exceptional difficulty of observing the relevant dynamics empirically”, says Marcus Hamilton of the University of Texas at San Antonio.

Direct evidence for the number of languages is almost entirely absent before the appearance of writing around 6,000 years ago, and remains fragmentary until quite recently. The researchers therefore combined ethnographic information, estimates of prehistoric population size, and statistical and social-computational modelling.

They began with ethnographic data from 171 hunter-gatherer and fisher societies whose traditional subsistence and mobility had not been profoundly transformed by contact with food-producing populations. These data allowed the researchers to estimate the likely distribution of ethnolinguistic group sizes near the beginning of the Holocene.

The team then combined these estimates with reconstructions suggesting that the global human population 12,000 years ago was between approximately 4.4 and seven million. Assuming that ethnolinguistic groups at that time generally corresponded to distinct languages, the models produced an early-Holocene estimate centred on roughly 4,500 to 6,200 languages, although broader plausible estimates ranged from around 3,300 to 7,800.

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“One of the first surprises was that the world immediately before agriculture was probably not exceptionally rich in languages. There were most likely fewer languages than there are today. Linguistic diversity then grew alongside the human population for thousands of years”, says Russell Gray, Director of the Department of Linguistic and Cultural Evolution at the Max Planck Institute for Evolutionary Anthropology in Leipzig.

Tens of thousands of languages

Agriculture, technological innovation and more stable food production allowed the global population to expand dramatically. At the same time, however, societies became larger, meaning that progressively more people could share the same language.

To capture these opposing processes, the researchers modelled thousands of possible trajectories connecting estimates at the beginning of the Holocene with the present. The models allowed the number of people per language to increase over time, while incorporating independent reconstructions of global population growth.

Although the precise trajectory remains uncertain, the models consistently produced a striking general pattern. Language diversity increased over most of the Holocene and typically peaked between 1,000 and 3,000 years ago. Many trajectories imply an approximately tenfold increase from early-Holocene levels, placing the peak number of languages in the tens of thousands.

“The most unexpected result is how recent the peak appears to have been. The period of greatest linguistic diversity may have occurred not in the remote Palaeolithic, but during the era of expanding states and early empires”, says Claire Bowern of Yale University.

The authors describe this period as a linguistic “golden age”. It has largely escaped previous discussion because most surviving historical records were produced by the expanding societies whose languages eventually became dominant.

The linguistic golden age was followed by a rapid decline, particularly during the last two millennia. The results therefore challenge the view that the present language-endangerment crisis began only with European colonial expansion around 500 years ago.

European colonialism unquestionably intensified language replacement on an enormous scale. The new models suggest, however, that the process had deeper roots in the expansion of earlier multinational states and empires. Such expansions brought previously separated populations into sustained contact and spread dominant languages together with political institutions, technologies, cultural practices and pathogens.

The model does not identify which particular empires, regions or historical events caused the global decline. Rather, it shows that a very large reduction in linguistic diversity must have taken place before the present.

Today’s languages passed through a bottleneck

This loss means that the languages spoken today are not a representative sample of those that once existed. Languages associated with expanding populations were disproportionately likely to survive, while the languages of absorbed, displaced or declining populations disappeared.

This historical bottleneck may also have altered the global frequency of grammatical structures, speech sounds and other linguistic features. Researchers often explain common features by suggesting that they are especially easy to learn, efficient to communicate or well suited to human cognition. The new study suggests that demographic expansion and extinction must also be considered.

“The languages we see today are the survivors of a massive and highly selective historical bottleneck. A linguistic feature may be common not because it is inherently superior, but because it happened to be carried by populations that expanded. Extinction may have shaped linguistic diversity much more profoundly than we previously appreciated”, says Damian Blasi, lead author of the study and researcher at the Catalan Institution for Research and Advanced Studies (Icrea) and Harvard University.

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Because languages are often transmitted together with religious practices, kinship systems, social institutions and other forms of cultural knowledge, the authors argue that this bottleneck extended beyond language. Many cultural traditions may also have vanished without leaving direct historical evidence.

The researchers emphasise that the study provides a coarse global reconstruction rather than a direct count of prehistoric languages. Its estimates depend on assumptions about early ethnolinguistic group sizes and the long-term relationship between population and language numbers. Regional histories undoubtedly differed, and short-term collapses caused by warfare, disease and environmental disruption cannot be individually reconstructed by the model.

Nevertheless, the central pattern persisted across a wide range of modelling conditions and alternative assumptions. The results suggest that the history of language diversity was not a simple, continuous decline from a highly diverse Palaeolithic world. Instead, linguistic diversity rose with human population growth, reached an extraordinary but short-lived peak, and then underwent a severe global contraction.

Original Article: The rise and fall of language diversity through the Holocene; Science; DOI:10.1126/science.adx4343

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