MLP: It's an exception
It's the most difficult thing about English: It seems every rule has its vexing exceptions, amusingly illustrated in this anonymous poem:
“We’ll begin with box, the plural is boxes,
Yet the plural of ox is oxen, not oxes.
One foul is a goose and two are called geese,
Yet the plural of moose is never called meese!”
Your Mrs. Language Person’s latest lament decried apostrophic abuse, its pitiful pilfering in plurals vs. possessives (a.k.a. the two faces of "s").
To quickly review, Dear Reader, poem notwithstanding, please add "s" to make most words plural, but precede with an apostrophe ('s) for possessives.
Now isn’t that simple?
Except when an apostrophe substitutes for missing letters, such as "isn't" made short for "is not." Except when it comes to its, and it's. (And before you say, "Those are incomplete sentences," and "Don't begin a sentence with 'and,'" chalk those up to stylistic license. Being a journalist must have some benefits.)
Which brings the struggling grammarian to that vexing exception: To make "it" possessive, such as, "its engine was on fire," we do not use the apostrophe.
Why? Confusion is likely, as if English wasn’t confusing enough. We use “it’s” as a contraction to mean, “it is.” Were there no exception for the possessive “its,” how might the unwitting reader know whether a possessive or a contraction is meant?
So often does one use the word "it's" to mean "it is" ("it's a fine day" and “it’s a ridiculous column) that to use the apostrophe ('s) to refer to both contraction and possessive would be too perplexing.
The solution for “it,” then, is to make its possessive look like a plural – just add “s” and it’s (it is) clear.
If you think that's (!) all for exceptions, woe is you, Reader. The plural possessive dilemma raises its (!) ugly head for nouns ending in s, x, ch, sh, or z. Consider the Joneses, as in don’t bother keeping up. Does one write, "the Jones' house" or the "Jones's” or perhaps even, the Joneses’?
Try two out of three. One Jones is Jones. Two are Joneses, with an “e” added as a general rule to make plural any noun ending in “s,” “x,” or “ch,” such as churches, boxes, and Joneses. That’s why the plural possessive must begin with the singular or plural spelling, then consider the apostrophe: Mr. Jones’s iguana and the Joneses’ spaceship (those Joneses are an interesting bunch).
Note: To make plural a regular noun ending in “z,” one must first double the z (no idea why), then add the “es,” as in quizzes. No, there won’t be one.
Note reprise: Why not the Joneses’s as a possessive form? Isn’t this exception obviouses’s from the unpalatable spittle when you said it? How uncouth.
One more plurality in parlance bears mention. Your MLP is a haughty, cranky old biddy, so don’t let her catch you making this common faux-pas, lest she unleash a string of expletives in your direction (betwixt us, Dear Reader, she’s getting ornery in her dotage).
When making plural a compound noun, please remember the plural belongs with it. That poor, lonely little “s” feels lost without her intended companion.
Therefore, your MLP has lovely "daughters-in-law;" it’s (!) incorrect to say, "mother-in-laws” because — heaven forbid — one means multiple mothers rather than laws. The words mother and daughter are the subject nouns, so these are what become plural by adding an "s."
Then why do we accept cupfuls, you ask, when this rule would make it cupsful? Alas, once so such cups were, yet more inexplicable exceptions eroded by time and misuse.
Worse, English speakers are eroding languages beyond their own. While colleges stay true, outside the hallowed halls “alumni” is accepted as singular and “stadiums” as plural. No, no! Shame!
These are Latin words with endings born of Latin rules: Alumnus (male singular), alumna (female singular), and alumni (plural). Similarly, the Greek-Latin word stadium is one and two are stadia. Don’t we have enough exceptions without inventing more?
"When comforting a grammar Nazi, I always say softly, there, their, they're."
Mrs. Language Person and Sholeh Patrick are word-weary columnists for the Hagadone New Network. Contact them at Sholeh@cdapress.com.