Where Do You Really Need a Comma? A Punctuation Primer
Punctuation might not be the most interesting part of writing, but it's more important than I think many writers really acknowledge. It's what molds words into coherent thoughts, bringing structure that guides readers to the correct meaning. At the same time, it helps to shape the rhythm and pacing so readers to hear it in the right voice and cadence.
I've been doing a lot of proofreading and line editing work recently, which means that I've been thinking a lot about punctuation. Creative writing is trickier to proofread than articles or web copy because not everything is a hard-and-fast rule. There are some absolutes, sure, but other conventions are a matter of taste and style, which means a pass for correctness is more about consistency within the manuscript than it is following every line of a grammar guide to the letter. That said, something I've come to realize over my years of reading other people's fiction as an editor: punctuation usage is one of the clearest signs of a writer's maturity in their craft. Professional writers understand which rules are flexible, along with how, when, and why to bend them, and are intentional with every piece of punctuation they place in their prose.
Something else I've learned as an editor is that there are some punctuation marks writers struggle with more than others. I'd say they exist in three tiers:
- The gimmes: Periods, question marks, ellipses, apotrophes, and parentheses. The rules for these are straightforward and most writers above the super beginner level understand how to use them.
- The semi-tricky: Colons, semicolons, quotation marks, and hyphens. The rules for these are slightly more complex, or they have multiple potential functions, and there are common errors writers make when using them.
- The super-tricky: Commas and em-dashes. The rules for these are squirrely and can vary depending on the style guide, and even experienced writers often don't know the correct usage.
Mistakes can still happen with the gimmes, but that's what they are—the writer just forgot to type a period or ending parenthsis, but they know it's supposed to be there. Those second two categories are where I'm most likely to see writers who clearly aren't sure about the rules. So I thought it might be helpful to do a quick rundown on the rules as they apply to fiction.
The semi-tricky
Let's knock these ones out first, because they're ones that most writers get mostly right.
Colons
There are a few potential uses for colons:
To introduce a list (Ex: There were three things on the sandwich: bacon, lettuce, and tomato.)
To introduce a quotation (Ex: As Captain Picard said: “Make it so.”)
To set off a word or phrase that you want to emphasize (Ex: He had come for just one reason: revenge.)
To connect two ideas when the second one explains or answers the first. (Ex: There was only one option: to keep moving forward.)
Colons are also used for things like times, ratios, and subtitles, but within the prose those are the main ways you'd use them. The biggest mistakes I see writers make with them:
- Using a colon like a semicolon. A colon can connect two complete ideas, but only if they're related in the ways described above. To simply link two related ideas, a semicolon is the correct choice.
- The phrase before the colon needs to be a complete sentence, which is a rule that writers sometimes neglect to follow
Semicolons
There are two potential uses for semicolons:
To link two complete sentences that are related to each other.
To separate items in a list when the list items have commas.
The first use is by far the most common. A good rule of thumb for whether you can use a semicolon is that the two phrases should also be grammatically correct if you used a period instead. The semicolon just makes the connection between them stronger and has a slightly different rhythm, with a mental pause that's somewhere between a comma and a period. The most common mistake people make with semicolons is using them when they should actually use a comma, and doing that mental check to make sure both sides are a complete sentence is the best way to avoid it.
Quotation marks
There are a few ways that double quotation marks (“quote”) can be used:
To signal spoken dialogue or a direct quote.
To enclose the title of a song, story, or poem.
To convey skepticism or that a word is being used ironically, sarcastically, or as a euphemism (Ex: The cafe's “fresh” bread was baked a week ago.)
There are also single quotes ('quote') which are primarily used for quotes contained within quotes (Ex: Then Jane said, “But Tommy said, 'I didn't do it,' and I believe him.”). Some people prefer single quotes for showing skepticism or irony to differentiate them from direct dialogue, which can be a correct use as long as it's done consistently.
Some mistakes I see people make with quotation marks:
- Using quotation marks to emphasize words. For straight emphasis, without adding any slant meaning, italics or all caps are a better way to go.
- Incorrect punctuation around quotation marks. If the quotation mark encloses dialogue or a quote, punctuation marks like commas, periods, and question marks should go within the quotation marks. If the marks just enclose a title or word, American English says to still enclose the punctuation, but British says to leave it on the outside.
Hyphens
Along with uses like writing dates, hyphens are commonly used in a few ways in prose:
To connect words in a compound modifier (a multi-word descriptive phrase) that comes before a noun. (Ex: The best-selling book, the seven-year-old kid)
To join the parts of a compound word (Ex: Mother-in-law)
In written numbers
To connect prefixes and suffixes that would create double letters or might otherwise be misread (Ex: Co-op, re-creation), or attach prefixes that always use a hyphen (ex- and self-).
There are also some addendums to those rules above, and these are the parts that I usually see trip writers up. These include:
- A hyphen shouldn't be used in a compound modifier when the first word is an adverb ending in -ly (Ex: I entered the brightly lit room.)
- Multi-word modifiers that are proper nouns are never hyphenated
- When “all” is part of a compound, it's hyphenated when it's being used as an adjective both before and after nouns (Ex: The god was all-knowing), but not hyphenated when it's being used as an adverb (Ex: The lights flickered all at once).
Other common mistakes I see around hyphens:
- Compound modifiers that come after a noun aren't hyphenated, even when it's correct to hyphenate it before the noun
- The hyphen is a different punctuation mark than an en-dash (used for ranges) or an em-dash (which we'll get to), so make sure you're using the right mark length for the situation
The super-tricky
With all those punctuation marks above, the rules are mostly clear and make sense, and are relatively easy to explain and understand. When writers misuse them, it's usually because they don't understand one of the secondary uses or more nuanced rules.
With em-dashes and commas, that is not the case. Each of them has its best recommended uses, but they also have a lot of wiggle room and space for stylistic variation. This makes them both very powerful and somewhat infuriating, especially when you're in the proofreading stage and want to make sure a piece of writing is exactly right. Here are the basic rules for each:
Em-dashes
So something else you'll see with both of these is that they have a lot of potential uses, which is one of the reasons they're so often misused and misunderstood. An em-dash can be used:
To show an interruption in dialogue, or in thought or action when used in narration. (Ex: I started left—then juked right when I saw my opponent shift his weight.)
To insert an aside, often one that interrupts the flow of thought or is being presented with emphasis. (Ex: I couldn’t believe—after everything we’d been through—that he would betray me.) In this way, it functions similar to parentheses, but has a more immediate feel.
To create emphasis or a dramatic pause at the end of a sentence (Ex: She saw him for what he was—dangerous.) In this way, it functions similar to a colon.
To connect two independent clauses. In this way, it functions similar to a semicolon but feels punchier and more abrupt. (Ex: I’d already called twice—I didn’t see a point trying a third time.)
They can also function in the same way as colons in their other uses, or be used to show that words were unspoken or censored, similar to an ellipsis, but the uses above are the most common.
The biggest mistake I see writers make with em-dashes is, honestly, overusing them. They're a punctuation mark that conveys a sense of action and quick movement, which makes them very appealing. But that also means they create a lurching, stilted rhythm that can get tiring for the reader when too many happen too close together.
Em-dashes also need to be treated similarly to colons and semicolons when they're being used to link entire sentences. The clause before the em-dash needs to be a complete thought, unless the em-dash is being used as an aside or interruption. It's those “excepts” that make this punctuation mark tricky.
Commas
Commas are the most difficult punctuation mark to learn the full rules for. Not only are there a lot of them, but they change between style guides and versions of English, and the rules are often different depending on the context. There are firmer rules about comma use in something like a scholarly article, for instance, than there are in a work of fiction.
That said, there are some places that you always need to use a comma, no matter what kind of writing you're doing:
To separate items in a list
To separate equally weighted adjectives in sequence before a noun. (Ex: “the wide, dusty path” but “the wide gravel path”) If the sentence would sound just as natural with the two adjectives flipped, then there should be a comma between them.
Before a direct address in dialogue
Before a coordinating conjunction that joins two independent clauses (Ex: He waved to her, but she was already driving away.)
After an introductory word or phrase (Ex: After school, we went to the mall.)
Around phrases that are nonessential and nonrestrictive. (Ex: The travelers, weary from a long journey, shuffled into the inn.) In other words, if removing the phrase wouldn't change the core meaning of the sentence, then it should be set off by commas (or paired em-dashes).
To set off interjections or interruptions in a less abrupt way than with em-dashes. (Ex: The boy, not the dog, had broken the plate.)
There are also some places where a comma should never be used, like:
Between a subject and its verb
Between adjectives in sequence that aren't equally weighted
After a conjunction
To join two independent clauses that aren't linked by a conjunction (Ex: “Joe called, Bob answered” is incorrect. It should be “Joe called; Bob answered” or “Joe called, and Bob answered.”)
And we're not done yet! There's another set of places where a comma is sometimes used, or can be used, or is only correct some of the time, like:
Though commas generally shouldn't be used before “because”, they should be used if the meaning of the sentence would otherwise be unclear (Ex: “Jack didn't go, because he was mad at Jill.” Without the comma, it's not clear whether Jack did or did not go).
While a comma is always correct between complete clauses joined by a conjunction, the comma can be omitted if both the clauses are fairly short. Exactly how many words counts as “short” is a matter of interpretation, but generally is around 5 words or under.
Similarly, the comma after an introductory word may be omitted if the phrase that follows is short.
Commas are optional around words like too, though, either, or also when they’re used as interjections. Generally, they read slightly gentler and with a slower pace with commas, but will read faster without the comma.
Within dialogue, commas are sometimes used in otherwise non-grammatical ways to signify a pause or breath. An ellipsis or em-dash can also be used for this. Generally, an ellipsis is going to read like a longer pause, while an em-dash is going to read as more abrupt, and the comma reads like a short, softer break.
An optional comma may be added in complex sentences, where separating words or phrases would add clarity to a passage that is currently ambiguous or confusing.
The truth is, when it comes to those more nebulous uses, it often comes down to the level of lyricism the author is going for and the stylistic preferences of the editor who's preparing it for publication. For authors, I would say the most important thing is to be consistent and intentional with how you employ punctuation like commas and em-dashes. There's no single right answer in a lot of cases, and the punctuation choices you make are a lot of what shape your personal style and voice.
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