To be fair, that's nowhere near as daft as september, october, november, december. Latin for seven, eight, nine, and ten is: septem, octem, novem, decem. Those are the nineth, 10th, 11th and 12th months.
Which wouldn't be that weird, except that the earliest Roman calendar started in March and ended in December, having only 10 months!
The Romans were of course well aware that this left a gap of about two months between the end of one year in December, and the beginning of the next year in March. But they just didn't bother counting this period as part of the calendar year. Presumably because there was no agricultural reason to need accurate dates during winter.
AIUI, there is some confusion over whether this is actually the case. The pre-Julian calendar had 12 months, plus an optional intercalated month (they were aware that their ‘year’ had the wrong number of days, and periodically shoved in some extra time to patch it up). The 10 month calendar, if it existed, would have been very early and there’s not much hard evidence that it was actually used. Numa Pompilius, who was allegedly responsible, is a mythical figure and probably not an actual historical king.
I'm French and occasionally like to (re)read about the revolution period and every time I come to the calendar stuff I can't help but think "Really? This was stuff we wanted to spend time on?"
Edit: Whoops, correct eng -> latin nums