How did the language you’re reading this in come to exist? The Indo-European family of languages covers most of Europe, the Iranian plateau, northern India and parts of Asia. Its members are spoken by almost half of all living people, and they all stem from a common source. English, Hindustani, Spanish, Russian, Sanskrit, Greek, Latin, Norse and many others (more than 400 still exist) can all be traced back to this starting point: Proto-Indo-European (PIE). Laura Spinney’s new book tells the story of how a language that may initially have been spoken as a kind of lingua franca by only a few dozen people evolved into the mother tongues of billions.

The words we use feel inevitable. We take them for granted. But they began life about 6,000 years ago, when copper was being smithed in the lands to the west of the Black Sea. Spinney says “an aura of magic must have hovered around the early smiths, who drew this gleaming marvel from blue-green rock”. New language hovered around them, too.

Novel technologies needed a novel vocabulary to describe them. The goods produced were transported across the Black Sea, which required the language of travel and exchange, as well as words that prepared merchants to meet with bears, boars and lions. Smithing brought new specialisations: metallurgy, casting, mining, charcoal-burning. All had to be named.

As the traders travelled, the words they shared went with them across the Black Sea and then around the world: from the forests of Romania to the steppe of Odessa, now with the development of larger and larger settlements, now with steppe herders becoming global traders, now with roads, now with the crossing of the Volga, sped up by the wheel, and on to the edge of China.

Spinney draws on a wealth of recent evidence to tell this story, combining linguistics, archaeology and genetic research to trace the movement of people and their language. Making these links is not straightforward. PIE was not written down; it has been reconstructed by comparing the languages that evolved from it. The word for daughter, for example, is very similar in English, Sanskrit, Greek, Armenian and Lithuanian (daughter, dúhitr, thugátēr, dustr, duktė ). This has all been used to deduce the PIE word *dhugh2ter. (The h2 might have sounded like the French guttural r. The asterisk denotes that the word is reconstructed.)

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