The previous article looked at how physical evidence — a horse’s teeth — helped trace the origin of riding. This article looks at a completely different kind of clue — words themselves — and how they became a dating tool.
A word can’t exist before its referent does
It sounds obvious once you say it, but for a word to exist in a language, the thing it refers to has to already exist in the world. Ancient Egyptian obviously had no word for “smartphone,” because smartphones didn’t exist yet.
This obvious fact turns out to be a powerful dating tool. Proto-Indo-European certainly had words for “wheel” and “axle.” By linguists’ reconstructions, the mother tongue had at least five words related to wheels and wagons — two words for “wheel” (possibly referring to different kinds), a word for “axle,” a word for the “thill” (the pole connecting the animals to the cart), and a verb meaning “to convey, to go by vehicle.”
Archaeology already knows when the wheel was invented
And as for when the wheel itself, as a technology, was invented, archaeology already has a remarkably precise answer. The oldest images of wheeled vehicles, the oldest clay models shaped like wheels, and the oldest written sign meaning “wagon” — all of these appear, almost simultaneously, at sites across Eurasia dated to roughly 3400–3000 BCE. No trace of a wheel or a wagon turns up anywhere before that.
In other words, the solid conclusion from archaeology today is that the wheel, as a technology, simply did not exist before 4000 BCE.
Shared inheritance, not a borrowed word
There’s one more important point here. This set of wheel- and wagon-related words appears, as cognates descended from a shared root, across nearly every branch of the Indo-European family — from Celtic in the west to Tocharian in the east, from Baltic in the north to Greek in the south. If this had been a word borrowed later from one language into another, it would never have spread this widely, in such regular correspondences, across the whole family. The very pattern of its spread shows that these words were already created inside Proto-Indo-European itself, while it was still a single, unified language.
The one exception is the Anatolian branch (including Hittite), thought to have split off earliest of all. This branch shows no convincing wheel vocabulary. This leads to an intriguing hypothesis: the ancestor of Anatolian may already have split away from the main body of Proto-Indo-European before the wheel was even invented.
Why the word for wool is a weaker clue
The same logic can be applied to the word for wool. Proto-Indo-European had a word meaning “wool.” But turning wool into woven textiles only became possible after sheep were bred for long wool — and exactly when that breeding happened is far less clear than when the wheel was invented. For that reason, Anthony cautiously notes, the wool vocabulary is a weaker dating tool than the wheel vocabulary. Not every piece of vocabulary can tell you a date with the same precision — and that very carefulness is part of what makes his method trustworthy.
Summary
| Point | Detail |
|---|---|
| The basic idea | A word can’t exist unless the thing it names already exists |
| Wheel vocabulary | Shared across nearly every branch of Indo-European — evidence it was created inside the mother tongue itself |
| Link to archaeology | The wheel was invented around 4000–3500 BCE — so Proto-Indo-European must postdate that |
| A careful exception | The wool vocabulary is weaker evidence, since the date of sheep breeding is less certain |
In a nutshell — a single word, “wheel,” gives a dead language, Proto-Indo-European, a solid lower bound on its age.