These little guys are the root of so many grammar errors that I feel like they should have their own national holiday. Absent that, they should always trip your radar. They are central to the their/they’re/there issue, the it’s/its conundrum, and the your/you’re debacle, not to mention the possessive/plural fiasco. So, any time you type an apostrophe, ask yourself:
Have I created a contraction?
A contraction is a smushing together of two words to make one, such as “it’s,” “there’s,” “they’re,” and “you’re.” Those mean “it is,” “there is” “they are,” and “you are.” (They should not be confused with “its,” “theirs,” “there,” or “your.”) All of those words are contractions, which means that some letters have been removed to take two words and make them into one.
You can also create a contraction using any noun followed by apostrophe-S: “This weather’s miserable,” “That team’s unstoppable,” etc. This is most often done in casual writing, or if you’re writing dialogue, so it’s not as common as other contractions. All you have to do is see if you could substitute that apostrophe-S for “is”; if you can, your apostrophe is in the right place.
Is what I’ve written a possessive noun? Is it a plural noun? Is it both?
This one isn’t quite as complicated. If you’re wondering whether you want to use “dogs,” “dog’s,” or “dogs’,” just ask yourself if you’re talking about more than one dog, a possession of a single dog, or the possessions of multiple dogs. So, “my dogs enjoy cheese” refers to more than one dog, but none of their possessions. “My dog’s bone ” describes a single dog and the one bone he possesses. “My dogs’ bones” indicates the many bones of my many dogs.
If you're confused about whether you're using a possessive, just change the wording from "X's Y" to "the Y belonging to X," and if that makes sense, you've got a possessive on your hands.
Possessive pronouns: Are they trying to kill me?
Here’s where possessives are slightly messier: Possessive pronouns don’t get apostrophes. Words like “his,” “hers,” “theirs,” “ours,” “yours,” and “its” might trip you up. Most of us get “his” right, because we know we’ve never see “hi’s” in writing. “Her’s” looks a little less funny, but it’s never correct. (I suppose there is a dialect of English out there where “her is” would be used, and could be shortened to “her’s,” but this seems so rare as to be barely worth a mention.) “Our’s,” “your’s,” and “their’s” are also never correct. Most word processing programs have the decency to red-squiggle underline these mistakes.
Its/it’s is one of the most common mistakes out there, but if you can remember that “its” is a cousin of “his” — for example, “His job [the job belonging to him] is hard” and “Its greatest challenge [the challenge belonging to it] is the long hours,” both contain possessive pronouns — and that neither gets an apostrophe, you’ll do alright. You can also just test out whether “it is” fits in place of your its/it’s, and try to remember that the one with the apostrophe always means “it is,” but that might be trickier.
Hang in there!
Apostrophes can be tricky, but as I have already mentioned, knowing to look out for them is the first step to getting them right.