Raymond Chen's article today sent me off on a long investigation into the origins of the word twenty. Specifically, it was this section of his post:
April 19, 1775 marked the Battles of Lexington and Concord, generally considered to be the opening battle of the American Revolutionary War. Four score and six years later, on April 19, 1861, the Pratt Street Riot in Baltimore marked the first death of the American Civil War.
What jumped out at me was the 'four score and six', which is the same way that French people say eighty-six: quatre-vingts six. A lot of English speakers studying French have trouble with the French word for eighty, but I've always found it interesting.
My interest piqued today however, wasn't in the fact that the French say eighty as four-twenties, but that the French word for twenty is so different to the English one. I knew English word came from the Germanic, closely related to zwanzig in German. Originally, the word for twenty was the combination of the words for 'two' and 'ten', literally two-tens. It's still pretty obvious in English, if you kind of squint your eyes.
Looking at the French word for twenty, vingt, doesn't give that impression. The word is just one syllable, and doesn't resemble the French words deux or dix. Is it just a crazy French thing, or did this originate somewhere else?
Given I don't speak or read French well enough to read French etymology websites, none of my Google searches in English managed to track down the origin of vingt in French. Eventually, I stumbled across it by reading the Wiktionary page on the English word twenty. It happened to have a link to the Latin word, viginti, which is in fact the origin of vingt. (Searching on Google for 'vingt viginti' confirmed this, once I knew what I was looking for.)
Really, though, that had just moved the problem elsewhere. The Latin word viginti doesn't resemble the Latin words for two and ten: duo and decem. I'd confirmed it wasn't a French aberration, but where did it come from?
Many Google searches later, I managed to determine the origin of the Latin word for twenty, viginti. It derives from the Sanskrit vimshatí, which does in fact mean two-tens in Sanskrit.
Even more surprisingly, the Germanic words for two and ten actually come from this Sanskrit root as well. From that, we can really see the strangeness of linguistic drift over time. Starting from two root words used in the Middle East perhaps three thousand years ago, you can end up with two completely different modern words combining them—twenty and vingt.