DNA from more than 4,500 ancient people suggests that waves of migration helped spread early Celtic and Germanic languages across Europe, but DNA cannot show directly what language any person spoke.
In two studies published in Nature, researchers analyzed 712 newly sequenced genomes alongside DNA published earlier. They then compared population movements with archaeological and language evidence. For Germanic languages, the researchers identified a migration into Scandinavia from the Baltic region about 4,000 years ago.
That migration may have brought an early form of Germanic about 800 years later than some earlier theories suggested. Researchers also traced a later movement of people from southern Scandinavia into parts of what are now Germany, Poland and the Netherlands around 1,650 years ago. They also found migration back north around the time Old Norse emerged.
For Celtic, the team found ancestry linked to the Central European Urnfield culture spreading west between about 3,200 and 2,800 years ago. The ancestry reached areas that include Britain and Iberia. The findings support a Central European route for Celtic's spread, rather than some competing proposals focused farther west.
Researchers warn that genetic ancestry does not prove what language people spoke. People can adopt new languages without large-scale migration. Migrants can also change languages after arriving.
The studies therefore provide evidence about population movements that may have helped shape Europe’s language map, not a direct record of ancient speech.