How to Use Commas
As a writer and editor, I've seen many confused acts of punctuation. Without question, the comma holds the title for the most commonly misused mark.
And why not? It's approachable, enticing, and like the period, even has its own key on my mobile keyboard.
The comma's commonality positions it as a gateway mark, a red-carpet enticement into the harrowing world of punctuation. There it sits, waiting to be peppered onto text. Ready for all manners of syntactic atrocities.
But its commonality belies its versatility and complexity.
For the fun of it—I'm making a rather large assumption that you find semantics “fun”—let's go over the following uses of commas:
When used with conjunctions, they can combine independent clauses (i.e., full sentences).
They separate items in lists.
They signal the use of dependent clauses and appositives.
They create separation when moving prepositional phrases to the beginning of sentences.
They can be used as a rhythmic device or for emphasis.
Each section will start with its appropriate number and an example. Like this:
1. A comma can turn two sentences into one, but it can only do so with the help of a conjunction.
Oh my. That was quite sudden. We just jumped right in.
If you refer to the example sentence above, you'll see two independent clauses within it:
A comma can turn two sentences into one.
It can only do so with the help of a conjunction.
As implied by their label, both independent clauses can exist on their own, but they're complementary. They work better together.
Because the comma isn't as strong a mark as say, a semicolon (which I've covered before), it needs a conjunction to hold the two sentences together.
What is a conjunction? you might ask. I've been deprived of Schoolhouse Rocks and its earworm educational approach, you might add.
Over the course of my educational misadventures I picked up a simple way to remember them. I learned this from Tom Kloskey, who ran the writing lab at Rowan University when I was a tutor there:
It must be noted that English is a living language, and in the hands of a skilled writer, the FANBOYS acronym may grow in length. But generally, if you're having trouble with commas and conjunctions, that acronym is a good home base.
2. Commas can be used to create separation, clarity, and order between items in a list.
This example shows how commas can serve as structural signals. They allow us a beat to diagnose and understand what we are reading.
If we were to happen upon our current example in the textual wild, the comma after "separation" would give us a brief moment to recognize that yes, the similar noun "clarity" follows. And we'd know that we were reading a list.
I'd feel remiss if I didn't note that the last comma in our current example is known as the serial or Oxford comma. Some don't like or use it, but I do. I like the separation it offers.
If the period were a caboose at the tail end of a list, commas would be the couplings holding the train together. And I don't see why the last item in a list shouldn't get its own train car.
3. Commas, which can signal dependent clauses, can also signal appositives, phrases that further define the nouns before them.
Dependent clauses provide additional information to a sentence, but they would be considered fragments on their own. Two dependent clauses exist in our current example:
- “which can signal dependent clauses,” and
- “phrases that further define the nouns before them.”
Neither makes much sense out of context. So they're dependent on this independent clause for meaning:
“Commas… can also signal appositives…”
As a note, the appositive is a type of dependent clause, and it appears in the second use in our current example. Here are a few others:
Mr. Taylor, our resident conspiracy theorist, thinks milk is alien blood.
Audrey, my lab partner, does not think highly of my flirtatious pipette technique.
Plimpton, the family potbelly pig, ate my Feta cheese omelette.
And so on.
4. If we didn't have commas at our disposal, our writing would be rather dull.
This is a common use of the comma, and it adds a little variety to our sentence structure. In our current example, the opening prepositional phrase has been moved before the subject, and our comma is signaling the structural rearrangement. I'll move it to better explain:
Our writing would be rather dull if we didn't have commas at our disposal.
The sentence makes perfect sense both ways. But in the first case, we are alerted sooner of the conditional nature of the sentence (signaled by the preposition “if”). So our preference between the two versions of a given sentence may depend on whether we feel the preposition is important enough to move forward, or perhaps because one version rings truer in our literary ear.
5. Commas can be used for rhythm, for emphasis.
This particular use of the comma can be rather confusing. The confusion stems from its subtleties, as well as its proximity to being grammatically incorrect.
Using a comma for rhythm or emphasis is a stylistic choice, and as such, it can trigger the grammatical puritans and sentence diagrammers among us. (These people are dwindling in number, but they are fierce.) This comma use can also prove dangerous when in the hands of inexperienced writers, who sometimes embrace this use before learning the others.
For these reasons, I recommend two tactics for anyone confused about using a comma for rhythm or emphasis:
Abstinence: Avoid the confusion, and prevent readers from diagnosing your lack of comma expertise.
Reading: Dig into texts that interest you, preferably those that have been edited by a professional. Read them out loud, embrace their voices, and write down your favorite passages. Over time, you’ll learn this use of the comma through contextual observation and experience.
The reason I suggest comma abstinence and ol’ fashioned book reading is because this use attracts attention. For writers to get away with it—assuming their readers are careful and/or critical—it must be understood the comma was placed consciously and deliberately.
Writers should consider this comma use akin to breaking the rules, or taking poetic license. If writers use commas correctly throughout their texts, this comma use seems earned. If not, it's damning evidence of their comma ignorance.
The Rules Are There for the Reading
In my undergraduate and graduate studies, I met many misinformed writers who believed good writing stemmed from the ideas conveyed in the text.
I believe good writing stems from the writer's understanding of grammar. Grammar begets clarity. And when wielded skillfully, it becomes invisible—enabling the text to become a clear voice in the reader's mind.
Put another way, good writers care about their ideas and their readers. And they use grammar to serve both.
What's the best way to learn grammar? There are five steps:
- Read everything. Start with anything you can get your hands on that's interesting. Classics are good too. Find your favorites.
- Pay attention. Try to figure out what writers are doing in practice. Mark up books. Write down great passages in a notebook.
- Mimic. You won't get it right at first. But keep trying.
- Read your work aloud. Don't stop. Circle any snags and address them later.
- Repeat.
Good luck and godspeed, you comma adventurer.