Early hominins who sailed across oceans left indirect evidence that they might have been the first to use language
A real language lies behind reconstructed Proto-Indo-European, just as a real language lies behind any dictionary. And that language is a guide to the thoughts, concerns, and material culture of real people who lived in a definite region between about 4500 and 2500 BCE.
David W. Anthony • The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World
The picture, in the end, is of an odd species that stumbled into global dominance through a relatively quick succession of simple mistakes. A species forced to speak up, or let its helpless infants perish.