A Tip for the Possessive Apostrophe

Apostrophes need not be learning catastrophes
by Rolf Palmberg

What is the difference between

1. The boy's books are on the table, and
2. The boys' books are on the table ?

The position of the apostrophe in a noun (to indicate possession of something) often causes problems for ESL/EFL learners. Yet the rules are simple. In fact, learners only need to decide whether the possessive noun (the possessor, which, by the way, can also be a name) is singular or plural and whether or not it ends in -s in its written form.

The following rules apply:

1. If the possessive noun is singular, always add an apostrophe + s.
2. If the possessive noun does not end in -s (in its written form), always add an apostrophe + s.
3. If the possessive noun is plural and ends in -s (and this is a characteristic feature of the large majority of plural nouns), just add an apostrophe.

This is why you say James's books, the children's books, and even the boss's books. This is also why you don't know whether something belongs to one or several boys until you see the sentence in writing.

To simplify things further, all you really have to remember is Rule 3. If Rule 3 does not apply, always add an apostrophe + s.

(Note that American English does not always follow these rules.)