'Perhaps," an inquiring reader writes, with a whiff of hope mixed with exasperation, "you could tell me when the plural of 'millennium' became 'millenniums' instead of 'millennia'?"
Whose idea is this, anyway? Moreover, she's noted that other Latin-derived nouns (e.g., stadium) form their plurals with "s" rather than "a." Shouldn't they all change at once?
Well, perhaps not. My e-mail pal shouldn't ascribe too much logic to English usage. It's not a matter of Latin grammar. It's that different words work their way into English in different ways, and at different levels. One of the glories of English is its richness of synonyms, its range of options up and down the scale of formality. Some words are highfalutin; some are for "just folks," better suited to the kitchen table than to the floor of a legislative chamber. Still other words are more universal, used by a broad range of speakers in just about any context.
"Stadium" is one of these universal words. It's derived from Latin, but it has become a naturalized citizen of the English language. Some ballparks are known as "stadiums," and some as "fields." But no one pulling into a filling station to ask directions to Dodger Stadium in Los Angeles is going to feel he's putting on airs by calling it a "stadium." That's what it's called.
"Millennium," however, wasn't much in the public domain until the closing years of the 20th century; even historians deal more in centuries than in thousand-year spans.
The Monitor's dictionary, Webster's New World College Dictionary, Fourth Edition (the standard dictionary of the Associated Press, by the way), gives "millenniums" as the plural. It probably causes as much gnashing of newsroom teeth as any other single entry. The assumption here seems to be that those who use the word at all should be expected to know it's Latin. But a number of these Latin-derived terms have escaped from the groves of academe and the mills of bureaucracy to join everyday speech: words like "data," "agenda," "memorandum," and "media." Once they are out in the real world, their special plurals get banged up a bit. People tend to go with the more familiar "s" plurals - or forget that there ever was a singular.
A task to be done, for instance, is "an agendum," which suggests an ancient Roman with hammer and chisel, carving his to-do list onto a marble tablet. (I get a kick out of imagining what Latin would have been like as a language of not just sage proverbs and inscriptions on famous buildings, but ordinary conversation - you know, like, "Honey, I've got to work late tonight. Can you pick up the chariot from the shop?" But I digress.)
Changes in popular usage occur almost unnoticeably over time, like the erosion of a beach. Eventually they make their way into the dictionary. That's the point at which changes can seem abrupt to careful readers. What happens, quite concretely, is that a new edition of a newspaper's preferred dictionary is delivered and becomes "official" as of a given date, and the newspaper that wrote of millennia and memoranda on Monday prints millenniums and memorandums on Tuesday.
And so back to Dear Reader's question: "How is a regular ol' amateur writer like me supposed to keep up with these things?!!"
Alas, you'll have to do it the same way I do: Pick a good dictionary and cultivate the habit of looking things up.
But if, in your private correspondence with consenting adults, you use "millennia" as the plural of "millennium," well, your secret is safe with me.
• This appears with links at: http:// weblogs.csmonitor.com/verbal_energy