Misplaced apostrophes are everywhere: on billboards, in newspaper articles, advertisements and the Internet. This is very irritating, and often causes ambiguity. It is also one of the most common punctuation errors. I believe this problem comes from confusion about how apostrophes are used. So I will give a brief overview of how to use apostrophes properly.
Apostrophes (’) only do two things. They indicate missing letters or words, or are used to indicated possessiveness or belonging to. They are never used to indicate that a word is plural.
Examples of words with apostrophes that indicate missing letters or words include don’t (do not), they’re (they are), o’clock (of the clock), bo’s’n (boatswain) and ‘tis (it is). This is the most straightforward use of apostrophes.
The second usage, to indicate possessiveness, is a little trickier. A good rule is to see if the sentence makes sense when the apostrophe is replaced with “of the” or “belonging to”. For example, “The dog’s bone” makes sense if we say “The bone of the dog” or “The bone belonging to the dog”. However, “She wore two scarve’s” doesn’t make sense if we replace the apostrophe with “belonging to”: “She wore two scarves belonging to.” Belonging to what?
Another good rule to remember is that the word must be a real English word before the apostrophe (and ‘S’) is added. Thus “Ladie’s shoes” is incorrect, because “Ladie” is not a modern English word. (The correct form is “Ladies’ shoes”, referring to the shoes of more than one lady.) This rule is especially useful when dealing with plural possessive words.
If a plural word ends in ‘S’, “dogs”, then an apostrophe is placed after the ‘S’, “dogs’ bones”. However, if the word is already plural, the apostrophe goes before the ‘S’. A park for children would be referred to as the “children’s park” not “childrens’ park” because children is already plural. (“Childrens” is also not a real English word).
What do we do when a name ends in ‘S’, but we want to make it possessive? Where does the apostrophe go then? Even English professors quibble over this, but a good place to start is to think about how the word is said. If it sounds like there are two ‘Ss’, then write ’s. (Example: “an actress’s success”.) If it sounds like only one ‘S’, then simply put an apostrophe after the ‘S’, “Ulysses’ journey”.
A very common error involves the plural form of CD and DVD. The word for more than one CD is CDs, and more than one DVD is DVDs. CD’s refers to something belonging to the CD, like its case (the CD’s case is cracked), and the same for DVDs.
There are a couple of exceptions to the rules above. First, “its” and “it’s”. “It’s” is the contraction “it is”. “Its” indicates possession, but does not have an apostrophe. Thus we have the sentences “It’s (it is) over there” and “Its cover is yellow (the cover belonging to it is yellow)”. Also, the possessive form of who is whose. “Who’s” is a contraction of “Who is” or “Who has”.
Hopefully these guidelines have not made things more confusing. The most important thing to remember is if the apostrophe is not used to indicate missing letters or words, or to indicate belonging and possessiveness, don’t use it! This will make all sticklers (like me) much happier.
Finally, if anyone is interested in learning more about apostrophes, I would recommend the book Eats, Shoots and Leaves by Lynne Truss.