Today, half the world’s population speaks an Indo-European language, whose descendant tongues include English, Russian, Greek, Bengali, and dozens more. So it’s no surprise that generations of scholars have obsessed over the mystery of where Indo-European originated and who spoke it first.

A pair of papers published today in Nature offer some of the starkest clues yet: DNA evidence suggesting an early form of Indo-European was first spoken between 4400 and 4000 B.C.E. in central Eurasia, then spread widely 1000 years later…

The Yamnaya were cattle and sheep herders who adopted wheels and wagons around 3300 B.C.E. Within a few centuries, their genes appear across Eurasia, from Mongolia to the grasslands of Eastern Europe. “It’s the largest migration into Europe in the last 5000 years,” says David Anthony, an archaeologist at Harvard University who co-authored both new studies.

But Indo-European predates the Yamnaya, according to one of the new papers. It marshals data from archaeology, linguistics, and genetics—including more than 400 newly sequenced genomes from people living in the region—to argue the language family first emerged about 6400 years ago on the grassy plains north of the Black Sea, where a colorful mix of ancient people intermingled. This late Stone Age melting pot included fishers living along the river valleys, hunter-gatherers migrating from farther north along the catchments of the Volga, Don, and Dnipro rivers, and farmers from the foothills of the Caucasus.