Write well. Write often. Edit wisely.
To give our sentences variety and complexity, we include much more than the basic information in every sentence. We include digressions and asides, commentary, parentheticals, and other interrupters.
Our sentences are rich in meaning and full of a wide range of word groupings. Some of those groupings interrupt the main thrust of the sentence. And of those interrupters, some we want to highlight while others we want to de-emphasize.
Interrupters can provide character or narrator commentary, additional information, or even emphasis.
Interrupters can be appositives, adjectives, adverbs, names, participial phrases, absolute phrases, prepositional phrases, interjections, and commentary.
Interrupters actually interrupt the meaning and flow of sentences and must be set off with the appropriate punctuation so readers can make sense of the information contained within the interrupter as well as within the sentence as a whole.
Writers have three choices of punctuation to set off sentence interrupters—commas, parentheses, and em dashes.
When interrupters fall midsentence, always use a pair of punctuation marks to surround them. And be careful to not mix different punctuation marks. For example, don’t use a dash to begin the interrupter and a comma to end it.
The scarlet silk—the soft and beautiful square of it, was torn. X
The scarlet silk—the soft and beautiful square of it—was torn.
You’ll use pairs of commas for digressions or supplementary information much more often in fiction than you’ll use dashes or parentheses. Commas aren’t your only choice, obviously, but their use is far more common than the other two choices.
Commas allow the text to flow. They help make sections of text manageable without drawing too much attention to themselves. They also don’t draw extra attention to the text between them. Instead, the text is neutral, blending into the sentence. Comma pairs aren’t intended either as a means of accenting text or downplaying it. They do make sections of text easier for the reader to group together and to understand.
Pairs of commas can surround single words, phrases, and clauses. Interrupters of many types can be nestled within commas.
“The truth, Daniel, is that you shouldn’t have followed me here.”
Nedra, hoping to score at least sixteen points in the first half, had practiced the night before the game until her arms trembled.
The bride, serene and smiling, sauntered down the aisle.
The button, the blue one, was broken.
He ran, surprisingly, toward the growling grizzly.
Parentheses (in BrE, round brackets)
Parentheses are quite noticeable. While the text between them is downplayed, the punctuation itself stands out. For this reason, many recommend that there’s no place for parentheses in fiction.
I won’t go that far—plenty of writers use parentheses in first-person narration for snarky thoughts or humorous asides—but I will suggest you limit their use. Parentheses are actually unnecessary in first-person narration because every thought is the thought of the viewpoint character/narrator. You don’t need to set thoughts aside, as if the character is speaking out of the side of her mouth to the reader. Everything the character says is overheard by the reader.
You would, however, use such asides as a style choice to show that the narrator/viewpoint character is aware that he’s speaking to the reader or an audience.
A problem with parentheses is that they can seem too much like author intrusion, as if the author is filling the reader in with a wink and a nod. As if the author is pulling back the curtain and whispering from the wings.
Parentheses, because the punctuation marks themselves stand out, can also point to the mechanics behind the fiction, to the setup. And anything that distracts from the fictional world, pointing back to the 3-D world, can prevent the reader from getting lost in the fictional characters and their adventures.
Parentheses are necessary and quite useful for nonfiction. But for fiction, you may want to rethink or restrict them.
Exceptions, of course, if you want to imply that your narrator/viewpoint character is speaking directly to the reader. That’s rare these days, but not unheard of.
Unlike commas, parentheses can be used to enclose full sentences or even paragraphs. Information is de-emphasized when it’s enclosed between parentheses. It can be pulled out completely and never be missed because it truly is something other, something additional to the main thrust of the sentence.
~ A sentence containing text set apart by parentheses must be grammatical without the parenthetical element.
~ Punctuation interrupted by the information between the parentheses comes after the closing parenthesis.
~ Parentheses are always used in pairs.
My aunt Eleanor (a mean woman who had nonetheless shared her home with me) is currently traveling through South America. [No comma after me because there is no comma in the sentence without the interrupter.]
Lucy Mallory, the wildly famous pinup girl from the forties (and a friend of my mother’s), would be visiting in a week. [A comma is required after mother’s because it would be required without the interruption.]
The new receptionist was gorgeous (and a guy!); the CEO’s new assistant was brainy, snooty, and taller than Mr. Crandall; and the chairman of the board was shrewd, mixing up the executive floor the way she had.
The steak (rare) was ready, the corn (raw) was overbuttered, and the French fries (the cheapest brand available) were still frozen.
The success (as well as the failures) were the fault of the sales department. X
The success (as well as the failures) was the fault of the sales department.
~ Parentheses don’t have to fall midsentence; they can come at the end.
My brother is planning to get married on my birthday (the last day of June). [Note the period is outside the parentheses.]
~ If a full sentence is enclosed in parentheses, the period goes inside.
Our school’s JV team won all their meets. (The varsity squad lost all of theirs.) And the parents threw them an ice cream blowout.
The third sentence in the previous example refers to the JV team. Anything relating to the varsity squad must be included inside the parentheses. Or you could rewrite to give the varsity squad equal attention.
Our school’s JV team won all their meets. The varsity squad, however, lost all their meets. The parents of the JV kids threw them an ice cream blowout to celebrate.
Em dashes (in BrE, em rule)
Dashes highlight or emphasize interrupters. If you want information to stand out, if you want to draw attention to it, use dashes.
If the phrase or clause you’re setting apart already contains a comma, using dashes to set it apart from the rest of the sentence will help reduce reader confusion.
As with sentences with parentheses, the sentence interrupted by dashes must make grammatical sense without the information contained between the dashes. That is, if you removed the dashes and everything between them, the sentence must still make sense.
Alfie needed to eat his breakfast—cook, eat, and clean up—in less than fifteen minutes.
Sally liked me to read her fairy tales—she loved those featuring handsome princes—before going to sleep.
Sally liked me to read her fairy tales—she loved those featuring handsome princes—so I always included Prince Phillip. X
The previous example doesn’t make sense. The final section of text does not complete the beginning of the sentence; it instead takes into account the interrupter.
Better would be—
Sally liked me to read her fairy tales. She loved those featuring handsome princes, so I always included Prince Phillip.
~ If the interrupter already contains commas, use dashes rather than more commas.
The littlest child—cuddly, cute, and sweet, sweet, sweet—was passed from adult to adult over the course of the hike.
~ While you could use multiple sets of dashes in the same sentence, rewriting is often the better choice. As always, you don’t want the reader noticing your punctuation.
Alfred Tennyson—the gardener, not the poet—showed up twice a week—always five minutes early—without fail.
~ When a digression, aside, or comment comes at the end of a sentence, you can still set it off with a dash. Yet there is no closing dash.
My dog came running when I called—and I had to chase her down when she raced straight through the house and out the front door.
~ When dashes are used, omit punctuation such as commas. The dash replaces the comma.
After reaching for the nails—and knocking them over the edge of the roof—I let Hildy do the hammering.
After reaching for the nails and knocking them over the edge of the roof, I let Hildy do the hammering.
After reaching for the nails (and knocking them over the edge of the roof), I let Hildy do the hammering.
After reaching for the nails—and knocking them over the edge of the roof—, I let Hildy do the hammering. X
AmE uses no spaces between the em dash and the letters before and after it. BrE typically includes space at both ends (and if you include this space, use an en dash rather than an em dash), yet it does allow for the dash to bump up against the letters as an option. (Apparently the Oxford folks use the em dash without spaces.)
Interrupters between commas, parentheses, and dashes are not capitalized (unless they are proper names). A full sentence enclosed by parentheses does begin with a capital letter.
Parentheses are always used in pairs. Dashes are used in pairs midsentence, but you can end a sentence with a digression set off with a single dash. What you don’t want to do is mix one dash with one comma. If you need two punctuation marks, use two of the same mark.
Teddy—lost in the woods—grew sleepy and hungry.
Teddy, lost in the woods—grew sleepy and hungry. X
Teddy—lost in the woods, grew sleepy and hungry. X
The punctuation for interruptions, asides, and commentary need to be introduced at logical breaks in the sentence.
I need my medicine—my migraines can be horrible, my credit cards—and of course my passport. X
I need my medicine—my migraines can be horrible—my credit cards, and of course my passport.
Use commas most of the time, especially if you don’t need to draw extra attention to the interrupter or don’t need to play it down.
Use parentheses sparingly in fiction. The information within the parentheses is de-emphasized and might not have a place in the sentence anyway. Use parentheses when you want to downplay the information between them but also want to let readers know you’ve got something to tell them. Use parentheses when you want to make readers aware of the narrator, viewpoint character, or author speaking to them.
Use dashes when you want to accentuate the information between the dashes, drawing special attention to the material, maybe giving it a distinctive flourish. Also use dashes rather than commas when the interrupter or aside or comment already contains commas.
Use dashes rather than commas when a comma splice would be created without the dashes.
Sally liked me to read her fairy tales, she loved those featuring handsome princes, before going to sleep. X
Sally liked me to read her fairy tales—she loved those featuring handsome princes—before going to sleep.
Use a dash to set off material that otherwise might be separated from the sentence by a colon or a period.
I needed him—it was a yin-yang thing.
I needed him: it was a yin-yang thing.
I needed him. It was a yin-yang thing.
You’ve got options for punctuating interruptions, yet one choice will likely be better in one situation while another choice fits a different situation better.
Explore the use of the em dash—give your sentences a new feel and create a variety of sentence formats and rhythms. On the other hand, don’t overuse dashes. Readers shouldn’t find dashes in every other sentence.
Reduce the use of parentheses in your fiction if you use them often. Unless you’re trying to wink at the reader, sharing inside jokes and letting the reader know that you know he is there, consider not using them at all.
If you’ve got specific questions about when to use commas, parentheses, and dashes, ask in the comments.