Proto-Indo-European is the ancestral tongue of 400 languages and dialects, including English, German, Italian, Greek, and Hindi. It appeared in historic records dating back 3,700 years, but researchers have long debated over where and when Proto-Indo-European originated and how it spread. Some say it happened around 9,000 years ago in Anatolia (modern-day Turkey) and then dispersed along with agriculture; others think that it arose between 6,500 and 5,500 years ago in the grassy steppe lands of Ukraine and Russia, north of the Black and Caspian seas.

Now, two new analyses—one linguistic, one genetic—both offer evidence to support the Steppe Hypothesis, which suggests that language spread westward along with innovations related to pastoral farming: horse domestication, wheeled vehicles, and wool weaving. 

Using statistical modeling, a team of UC Berkeley linguists led by Will Chang calculated how quickly 207 sets of words from over 150 Indo-European languages (dead and living) changed over time. Based on the rate of change between ancient or medieval languages and their modern descendants, the languages that first used these words began diverging 6,500 years ago, according to a news release. This, together with a reanalysis of the family tree of Indo-European tongues, is consistent with an ancestral language originating in the vast steppe lands stretching from Moldova to western Kazakhstan. These findings will be published in the journal Language.

Another team, led by Harvard’s David Reich, generated genome-wide data from 69 Europeans who lived between 8,000 and 3,000 years ago. They also studied previously published data from another 25 ancient Europeans, including Ötzi the 5,300-year-old glacier mummy. 

Based on these analyses, the Yamnaya steppe herders in Russia from 6,000 to 5,000 years ago were descendants of preceding eastern European hunter-gatherers as well as a population with near eastern ancestry. Then, by around 4,500 years ago, the Corded Ware people (an example of their famous pottery is pictured above) were living in Germany and other parts of northern Europe. The team traced about three-fourths of their ancestry to the Yamnaya, indicating how a massive migration into central Europe from its eastern edge must have taken place. In fact, most present-day Europeans, Science explains, can trace their ancestry back to both the Corded Ware people and the earlier Yamnaya. And these migrants from the east brought with them technologies like the wheel, Nature reports, as well as their language, which likely originated in the steppes of Yamnaya. This work is available on the bioRxiv preprint server.