The origins of Sino-Tibetan languages

One of the most diverse language families in the world originated among millet farmers in North China around 7200 years ago, new research shows.

The Sino-Tibetan family is represented by more than 400 modern languages spoken by 1.4 billion people in China, India, Burma, and Nepal. 

After the Indo-European languages, which have roughly 3.2 billion speakers, it is the second largest family to have emerged over the past 10,000 years, and the two together account for nearly 60% of the world’s population.

Indo-European has received a little more attention from archaeogeneticists, phylogeneticists and linguists, however, and knowledge of the origins of Sino-Tibetan languages has been severely limited. 

That makes a new interdisciplinary study led by scientists from Germany’s Max Planck Institute for the Science of Human History, the Centre des Recherches Linguistiques sur l’Asie Orientale and the Centre de Recherches en Mathématiques de la Décision, both in Paris, more than welcome.

The team assembled a lexical database containing core vocabulary from 50 Sino-Tibetan languages, including some spoken a thousand or more years ago, such as Old Chinese, Old Burmese and Old Tibetan, alongside modern languages documented by field work. 

To compare them in a transparent way, they developed a specific annotation framework that allowed them not only to mark which words can be identified as sharing a common origin, but also which sounds in the words they thought were related. 

“A particular problem in identifying the truly related words were the numerous cases where languages borrowed words from each other,” says co-first author Guillaume Jacques. 

“Luckily, we know the history of particular languages rather well and could rely on techniques that we developed before to reveal the true history concealed by these borrowings.”

Using powerful computational methods, the team inferred the most probable relationships between the languages, allowing them to estimate when they might have originated in the past. They then looked at related words describing domesticates, which may reveal how agricultural knowledge spread through the region. 

This analysis suggested an origin of the Sino-Tibetan family in northern Chinese communities of millet farmers of the Neolithic cultures of late Cishan and early Yangshao. 

“The most likely expansion scenario of the languages involves an initial separation between an Eastern group, from which the Chinese dialects evolved, and a Western group, which is ancestral to the rest of the Sino-Tibetan languages,” says Laurent Sagart, who carried out the agricultural analysis.

Research leader Johann-Mattis List adds, with a touch of understatement, that they are “very excited” about their findings.

“Our approach combines robust, traditional scholarship with cutting-edge computational methods within a computer-assisted framework that allows us to use our knowledge of today’s languages as a key to their past,” he says.

The research is published in the journal the Proceedings of the National Academy of Sciences.