Earlier this week, one of my children asked me why eleven and twelve aren’t “oneteen” and “twoteen”, so I thought that would make an interesting blog topic today.
Both words have been around for centuries. Eleven was originally spelled as elleovene and came from an Old English word—endleofan—that appeared around the start of the 13th century. Ultimately derived from the Proto-Germanic ainalif, it literally meant “one left” (ainaz meaning “one” and lif meaning “left”) because in a base-10 system sometimes it’s handy to have a number that refers to what’s left over after 10.
The word “twelve” hasn’t changed much, originally written as twelf. It, too, came from a Proto-Germanic compound word that included lif: twalif (twa meaning “two” and lif, of course, meaning “left”). Like its predecessor, it meant “two left”.
This, of course, raises the question as to why the pattern switched as of thirteen. Unfortunately, we don’t seem to know. That’s the English language for you. :)