December comes from the Latin decem, meaning “ten.” It is the twelfth month. This name has been wrong for over 2,100 years—since the Romans added January and February to the year and pushed December from tenth to twelfth position. No civilization in human history has carried a labeling error for so long, with so little effort to correct it.
December is the logical endpoint of everything wrong with the English calendar. It is the final month, the last exhibit in a museum of accumulated linguistic debt. And it is, in many ways, the clearest case for reform: if even the word that means “ten” cannot be trusted to refer to the tenth month, then the entire naming system has lost its credibility.
Consider the total cost of the English month-naming system. Twelve months. Four categories of origin: gods (January, March, April, May, June), emperors (July, August), a festival (February), and wrong numbers (September through December). No internal logic connects them. No mnemonic helps with sequence. The learner must memorize all twelve individually, as if they were arbitrary codes—which, functionally, they are.
Compare this to Month One through Month Twelve. A single rule generates the entire set. Master Month One, and you understand the system. You can predict Month Five without ever having seen it. You can derive Month Twelve from first principles. This is not dumbing down. This is designing a calendar that works for the people who use it.
The case for retiring the Roman month-names is the case for retiring linguistic debt—words that cost more to learn and maintain than they contribute to communication. January through December is a 2,100-year-old credit card bill. It is time to pay it off.
Our Recommendation: Month Twelve. Ten is over. Twelve is correct. The clean calendar begins now.
This is a well-argued piece. I respect the logic. December should mean ten, and it doesn’t, and that is a problem with a clear solution.
However.
My twelve-year-old daughter just spent two hours on a Thursday night memorizing the word “crapulous.” She cannot tell you why October is the tenth month. She does not care. She cares about passing her vocabulary test on Friday so her GPA does not drop.
Fix December. Fix the months. I am with you. But while you are at it, fix the fact that somebody somewhere decided a seventh grader needs to know what “recumbentibus” means. That is the calendar reform I would actually show up to vote for.
— Michael Nguyen