For a long time, the assumption was that ancient history was a endless sea of thousands of small isolated tribes—meaning language diversity must have started at its highest point and steadily decayed. The new models show a very different story: a massive bell curve where language diversity peaked just 1,000 to 3,000 years ago before crashing into a severe bottleneck.

A shift from nomadic lifestyles could have triggered linguistic diversity before it then declined rapidly.

A new study coauthored by Yale linguist Claire Bowern suggests that tens of thousands of languages were spoken between 1,000 and 3,000 years ago.