Punctuating Parenthetical Word Groups

Downloadable version (Microsoft Word document)

Often writers will interrupt a sentence so they can add a comment.  If these comments interrupt the flow of a sentence, or if the comments are not essential to the meaning of the sentence, they are considered parenthetical. Parenthetical comments, whether one word or a group of words, should be set off by punctuation. Four marks of punctuation can be used to identify parenthetical words or word groups: commas, dashes, parentheses, and brackets.

Commas

Whether or not a word group needs a set of paired commas depends on whether it is restrictive or nonrestrictive. A restrictive modifier is a word or phrase that modifies a noun and is essential to the meaning of the sentence; therefore, it is not parenthetical. There are no commas around restrictive modifiers.

Example:     My dog Tim is very gentle with children.

In this case, the speaker is specifying one dog out of many dogs that he or she owns—Tim.

A nonrestrictive modifier is information that is not essential to the meaning of the sentence, requiring a pair of commas to set it off from the surrounding text. In this way the commas act like parentheses.

Example:     My dog, the one I named Tim, is very gentle with children.

The one I named Tim is a nonrestrictive modifier because it is non-essential to the meaning of the sentence.

Interrupters, words that interrupt direct quotations, are set off by commas.

Example:     "I love no love," proclaimed poet Mary Coleridge, "but thee."

Note: For more information on comma usage see the handouts Commas and Comma Splices and Fused Sentences.

Dashes

The dash can also be used to set off parenthetical material. Whereas a pair of commas sets off parenthetical material that is closely related to the sentence, paired dashes set off an explanation or thought that interrupts the flow of the sentence. There is no space between the dash and the words that it separates.

Examples:   The greatest Renaissance painters—Da Vinci, Michelangelo, Raphael—were all Italian.
Mr. Johnson—the one who screams at his kids’ soccer games—was hit in the head by a stray soccer ball.
I was—I know I was—leaving work when the phone rang.

In Microsoft Word, a dash can be created by pressing Ctrl+Alt+Num- (Control, Alt, and the minus key on the number pad) or by typing two dashes. On a Mac, press Alt+Shift+Hyphen. For more information on dashes see the handout The Colon, Hyphen, Dash & Semicolon.

Parentheses

Parentheses enclose words or word groups that are incidental or irrelevant to the main idea of a sentence.

Examples:   Well, only one student (Julie) completed all the problems.
After the holidays, the weight watchers (most of them anyway) begin to count calories.
Maria Davis rose and walked to the window (she had done this countless times over the last three days) and stared out at the empty street.

Brackets

Use brackets when you add a comment or explanation to material you have quoted from another source.

Example:   In Newsweek, Bert Lance was quoted:  "These accusations [those printed in the Washington Post] are, as I understand them, totally false."

Use brackets as parentheses when you enclose a word or word group within parentheses:

Example:       I am told that hunters respect the animals they hunt.  (How does one respect [i.e., hold in high or special regard, honor] something one kills?)

James Gunter, spring 2005
Based on a handout by Laura Hunter, Feb. 1993