Indo-European

Sometime around 4500 BCE, on the grasslands north of the Black Sea, a group of semi-nomadic pastoralists spoke a language that would become the ancestor of almost half the world's modern tongues. We call it Proto-Indo-European — no written records survive, but linguists have reconstructed it from the patterns shared by its far-flung descendants.

When these steppe peoples domesticated the horse and invented the wheeled chariot, they gained a mobility advantage that sent waves of migration across Eurasia. Some moved south through Iran and into India, carrying what would become Sanskrit and Persian. Others pushed west into Europe, seeding the ancestors of Greek, Latin, Celtic, Germanic, and Slavic languages.

Today, the Indo-European family stretches from Iceland to Sri Lanka, from Brazil to Siberia. Its branches include languages as different as Irish and Hindi, Russian and Portuguese — yet they all share telltale traces of that original steppe tongue. The word for 'mother,' for instance, echoes across millennia: Sanskrit mātṛ, Latin māter, English mother, Persian mādar.