But when to use an apostrophe, and when not to, is really a super simple thing, and yet it confuses so many people. Apostrophes mean possession, many people think, so they add an apostrophe to its or hers. Shudder.
Actually, the simple truth is: Apostrophes are used for contractions.
That's it. That's all. Apostrophes never pluralize and they never indicate possession. Now wait a minute, you might be thinking. Because there are times when you need to use an apostrophe with a possessive, and times when it might be acceptable to use one with a plural. For the first: it's not because it's a possessive, it's because it's a contraction. And for the second: it might be acceptable, but it isn't correct.
So, the simple rule for apostrophes again: Use an apostrophe only when your word is a contraction.
Before I get to how that works with those pesky possessives that happen to have apostrophes, here's an essay I wrote a million years ago when I was in charge of the About.com Creative Writing for Teens site (as I said last week, it no longer exists, though you may find parts of it archived -- or plagiarized -- here and there on the web).
Which Word: Plurals, Possessives, and Contractions
More Than OneMost nouns are made plural simply by adding s (or es if the word already ends in s or sh). So more than one dog are dogs, one horse plus another horse makes two horses, and you can be in one skirmish or several skirmishes. Then there are the irregular plurals like mouse becoming mice and knife knives, but that doesn't concern us here. The point to remember is that when you add s to make a plural, you add only the s, never apostrophe-s. So dogs is always dogs and never dog's if you're talking about more than one dog.
But That Is MineNouns are made possessive by adding s also. This is why people get confused. But it doesn't have to be confusing if you remember that to make a noun possessive you add apostrophe-s, and not just s all by itself. So to say that a bone belongs to a dog, you say that it is the dog's bone. A horse that belongs to Jonathan is Jonathan's horse. And so on.
But then what do you do if the noun or name ends with s already? There are two possibilities. One is to go ahead and add apostrophe-s after the s that is already there. The other is to just add an apostrophe. So you could say that a car belonging to Seumas is Seumas's car, or that it is Seumas' car. Adding both the apostrophe and the s is generally considered more correct, though either option is acceptable. The same two possibilities are available when making a plural noun possessive. You could say the dogs' bone or the dogs's bone in order to indicate a bone belonging to several dogs. To talk about the house where the Joneses live (more than one person with the last name Jones), you would say the Joneses's house or the Joneses' house. Writers usually use whichever is most like the way someone reading aloud would pronounce it; so a writer would probably write Seumas's car but the dogs' bone and the Joneses' house.
More Apostrophe-sesAnother place you get that old apostrophe-s is when you contract two words into one word (known as a contraction). Contractions don't always involve ses, of course; don't and isn't are contractions. But it's the ses that get confusing. All you need to remember is: in a contraction, the s always stands for another word (usually is, but sometimes other words like us). So that dog is running can become that dog's running and let us go swimming becomes let's go swimming.
Those Pesky Possessive PronounsAnother source of confusion is possessive pronouns. Pronouns are words that stand in for nouns, like me, you, she, it, us and so on. Unlike other nouns, pronouns never use apostrophe-s to become plural; they have their own special plural forms. To show possession, the dog that belongs to me becomes my dog; the dog is mine. So you get the forms me my mine, you your yours, he his his, she her hers, us our ours, it its its. The word its seems to give people the most trouble. The key is this: its is a possessive pronoun (possessive pronouns don't use apostrophes); it's is short for it is.
When Plurals Are Allowed ApostrophesNow I've already said that plurals never use apostrophes, and I stand by that, but some publications (and web sites) require the use of apostrophes in plural forms in special situations (and only in special situations). Those situations are ones where the s that makes the word plural might be confused with part of the word itself, in acronyms or abbreviations, and with numbers. So some newspapers, for example, specify that you must write how-to's rather than how-tos, CD's instead of CDs, and the 1990's rather than the 1990s. Personally, I think people are smart enough not to need those apostrophes, but if it makes the difference between selling an article and not selling one, I'll put the silly things in.
How To Keep It All StraightThat seems like an awful lot of detail to remember, but it's all logical if you stop to think about it. But to make it a little easier, just remember these rules:
- Nouns become plural with s or es (unless they're irregular), and never use apostrophes (except in some publications where some words, acronyms/abbreviations and numbers are required to have them).
- Nouns, including plural nouns (but not pronouns), become possessive with apostrophe-s (or sometimes with just apostrophe).
- Pronouns have special possessive forms and so do not use apostrophes.
- Contractions always use apostrophes to indicate that part of the word has been taken out to shorten it.
And that's it. Remember those four points, and you'll always know if you need to say its or it's, the dogs or the dog's.
In the million years since I wrote that article -- which I mostly still agree with -- I learned why it that possessive nouns use apostrophes, and it makes everything so much simpler. I think if they would just teach that one little bit of the history of English in school, a lot of people would never be confused about apostrophes. And if I'd known it when I wrote that article, I could have simplified my final list to:
- Only contractions use apostrophes.
Because the reason possessive nouns require apostrophes is because they are also contractions.
Once upon a time, in order to make a noun possessive, you have to make it awhile phrase. So to say that George owned this book, you'd write: George, his book. And, as language change, that phrase became one the was more conveniently shortened, contracted to George's book. In other words, George's is a contraction of George, his.
So how come we don't use Emily'r instead of Emily, her? I imagine it's partly because it's unpronounceable, but also because the default gender in the English language has long been male. (I won't say it always was, because there was a time when English -- or that which English evolved from (I don't recall the details and I'm too lazy to look it up) -- had a different set of pronouns).
So there you go. Apostrophes are only used for contractions, and possessives only have apostrophes if they are also contractions.