The apostrophe (’) is one of the hardest working punctuation marks in the English language. Not surprisingly, it’s also one of the most misused. Apostrophes can be confusing even for native speakers of English, but they aren’t difficult to master if you can remember a few apostrophe rules.
Debate has raged among grammarians over some of its more esoteric uses, but the rules for its two most important functions (possession and omission) are pretty clear. Apostrophes in English serve two basic functions; they show possession, and they indicate that letters have been removed from the original words in the process of forming a contraction (omission). They are not necessary for forming plural nouns or possessive adjectives (my, your, his, her, their, our, its).
1.a. Possession
This is what most of us call ‘apostrophe s’, and it is used to indicate that something or someone owns or possesses something or someone.
For example, if John owns a dog we would describe his pet like this: John’s dog. Another example: Mr Jones’s car.
Note that the apostrophe goes before the ‘s’. This is what you do with a singular noun.
When the noun is plural and ends in an ‘s’ on the end, the apostrophe goes after the ‘s’: E.g. Editors’ stress levels are dangerously high.
Use an apostrophe after the ‘s’ at the end of a plural noun to show possession. More examples: The parents’ bedroom; the Joneses’ home (the family Jones).
It is not necessary to add another ‘s’ to the end of a plural noun after the apostrophe. If a plural noun doesn’t end in ‘s’, add an ‘s’ after the apostrophe to create the possessive form. E.g. The children’s school uniforms.
Remember, a possessive noun needs an apostrophe and an ‘s at the end. If there’s already an ‘s’ there, you can just add the apostrophe. If there’s no ‘s’, you have to add both – first the apostrophe, and then the ‘s’.
Special Cases and Variations
Some writers and editors add only an apostrophe (’) to all nouns ending in ‘s’. E.g. Mr Harris’; the class’ lunch break. This practice is not recommended.
And some add an apostrophe + ‘s’ to every proper noun, be it Mrs Hastings’s or Mr Jones’s.
One method, common in newspapers and magazines, is to add an apostrophe + ‘s’ (‘s) to common nouns ending in ‘s’, but only a standalone apostrophe to proper nouns ending in ‘s’.
E.g. The glass’s shelves; Mr Jones’ brown shoes.
A special case is a singular noun that ends in ‘s’. E.g. Ross’s red car.
While there are writers who add just an apostrophe to show singular possession of a name ending in ‘s’ or ‘z’. It is recommended for good grammar’s sake, to add another ‘s’. Exceptions to this rule are for biblical names and words. E.g. Jesus’.
E.g. Bill Williams’ car OR Bill Williams’s car; Mrs. Sanchez’s children OR Mrs Sanchez’ children.
To show plural possession of a name ending in ‘s’, ‘ch’, or ‘z’, form the plural first; then immediately use the apostrophe.
E.g. The Williamses’ car; the Birches’ house; the Sanchezes’ children.
1.b Possessive Pronouns
Sometimes, however, possession does not require an apostrophe. This is when possessive pronouns are used. A pronoun is a word that stands in for a noun, such as ‘I’ or ‘you’. The possessive pronouns are my, mine, your, yours, his, her, hers, its, our, ours, their, theirs
All these words indicate possession, some of them end in ‘s’, but none, I repeat, none of them ever need an apostrophe. Not once, ever!
E.g. That book is hers. These magazines are ours. That DVD is yours, but its owner doesn’t want it.
2. Omission
An apostrophe has long been used to indicate that some letters have been omitted from a word. The word ‘it’s’ is an example of a contraction. That is, two words have been contracted to form one, in this case ‘it’ and ‘is’. E.g. It’s time to make a decision.
Other examples are:
They’re (they are), we’re (we are); they’ll (they will), you’re (you are); they’ve (they have); aren’t (are not).
The one exception to this rule is the contraction ‘won’t’, which is ‘will + not’.
Apostrophes can also be used to indicate that some letters have been left out of a single word:
E.g. Can’t (cannot); Jo’burg (Johannesburg).
Final Thoughts
Don’t lose the battle of the apostrophe. First, ask yourself if the word owns or possesses something. If the answer is yes, check whether it’s a noun or a possessive pronoun. If it’s a noun, it needs an apostrophe. If it’s a pronoun, disregard all urges, however strong, to put an apostrophe in it. If the word doesn’t own anything, have a look to see if there are any letters missing, and put the apostrophe where the missing letters should go. The key is to think about how the word is used and what the apostrophe is for, and you’ll be the winner.