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Fairly frequently I’ll get questions about comma use. I’ve not yet addressed the use of commas with restrictive and nonrestrictive clauses, so we’ll look at that issue in this article.
When is a comma necessary and when can it be dropped?
What are restrictive and nonrestrictive clauses and what do they have to do with commas?
What about nonessential phrases?
And what’s an appositive? It has something to do with commas too, right?
If you’re asking your questions this way, you probably learned the rules in school and are looking for a refresher. For those who have no idea what these questions are in reference to, let’s look at examples. You’ll recognize the concepts and the phrases, whether or not you know their fancy names or the rules. And don’t worry, it’s not the names that are important. It’s how you use the concepts and the commas that we care about.
For purposes of this discussion, restrictive and essential will be used interchangeably, as will nonrestrictive and nonessential. Essential and nonessential seem to make the explanations more understandable.
Let’s start with appositives.
My wife, Heidi, is a professional bowler.
Helga, my wife, is a professional baker.
My wife, a woman with no sense of fear, is a professional bomb tester.
My wife, the CFO of her company, reads spy novels by the bucketful.
A beautiful woman, my wife has learned to graciously accept compliments.
The words in blue are appositives. They are simply nouns or noun phrases that rename another noun.
They are set off by commas in these sentences not because they are appositives, though appositives are often set off by commas, but because the information they provide is nonessential. Nonessential appositives are set off from the rest of the sentence with commas.
A phrase, clause, or word is nonessential if the sentence makes sense and is complete without it. Nonessential phrases can be moved around in the sentence or cut from the sentence and the sentence will still make sense. You can see that in each of the sentences above, removing the words in blue doesn’t create a nonsense sentence; the meaning is still clear.
But what about these sentences?
My wife Heidi is a professional bowler and my wife Helga is a baker.
My friend Corwin told me he’d cheated on his wife.
My best friend, Corwin, told me he’d cheated on his wife.
We’re still considering appositives, a renaming of the nouns, but this time the conditions are different, at least for the first two sentences.
The narrator of the first sentence apparently has (at least) two wives, and they practice different professions. The names in this sentence are essential to convey the full meaning of the sentence. Essential information is not separated out by commas.
In the second sentence, Corwin’s name is essential because presumably the narrator has several friends. It’s not likely that all confessed they’d cheated on their wives. Corwin’s name is essential information so the reader knows who is being spoken about.
When we’ve said my best friend, however, in the third sentence, Corwin’s name is nonessential. We’re not saying that the name is unimportant. We are saying that best friend, without the name, is sufficient to identify the cheater. It’s likely the narrator has only one best friend.
To help you remember whether a phrase or word needs to be surrounded by commas, try putting the phrase within commas and then taking that phrase or word out of the sentence. If the sentence is clear without it—and if it conveys sufficient information—then it’s nonessential and does need commas.
If the sentence makes little sense or is incomplete without the phrase, the words are essential and don’t get commas.
A quick test—
If you’re talking about an appositive and that appositive refers to one of a kind—a spouse, a best friend, or the greatest or worst of anything—then the appositive is nonessential and gets commas. (Just remember that spouses—my husband, Jasper, walks to work—get commas.)
But what of that last sentence in the first grouping? A beautiful woman, my wife has learned to graciously accept compliments. What about the appositive in that sentence?
As the sentence is written, the appositive (a beautiful woman) is set off by a comma. It doesn’t follow the noun, but comes before it. There’s no comma after wife because it’s just a noun, the subject of the sentence. No second comma is necessary unless the sentence is reworded—My wife, a beautiful woman, has graciously learned to accept compliments.
Note: For more confusion, some style guides are now recommending that short appositives should not be set off by commas. Until you know differently for a specific publisher or publication, include the commas.
Okay, that covers appositives. What about other words or phrases or clauses?
You’ll be relieved to know that the principle is the same. Essential phrases don’t get commas. Essential phrases are part of the foundation of the sentence and don’t need to be separated out in any way. Nonessentials can be plucked right out from between the commas. Essentials blend in; nonessentials (which can be taken out), stand out.
So, let’s look at some other circumstances when the essential/nonessential issue comes up.
This is the one that causes a lot of confusion. And even when someone remembers the rule—which is preceded by a comma—the basis for the rule is often forgotten, making the use of both which and the comma unnecessary.
That is used for essential phrases and which is used for nonessential. (At least this is true in American English. In British English, which is accepted for both essential and nonessential phrases, though that is always used only for essential.) Some American writers follow the British practice and mix and match their thats and whiches.
However, you cannot simply pair a comma with which and claim the sentence is written correctly. If, because of the intended meaning, the phrase should be an essential one that uses that and no comma, you can’t use which and a comma. Doing so changes the meaning of the sentence. So even if the form is right, the meaning may be wrong.
It’s not simply a choice between using that without a comma and which with a comma. It’s not an either/or option; depending on the intended meaning of your sentence, one option will be correct and the other will be wrong.
That is, the rules reflect the meaning of the sentence.
Have I confused you? Let’s look at examples.
He reached up to straighten the portrait that hung on the north wall.
I was ecstatic over the late snow that quickly reached the tops of the cars in the street.
He reached up to straighten the portrait, which had been knocked askew by the racing children.
I was ecstatic over the late snow, which piled up in the street and soon reached the tops of the cars.
The differences between the first sentences in each pair should be apparent.
The first sentence, with that and no comma, tells the reader that it is the portrait hanging on the north wall that’s being straightened. There may well be other portraits in the room, but not on the north wall. The information beginning with the word that is essential to identify which portrait is being discussed.
In the first sentence of the second set, the discussion is about one particular portrait. It may be the only one in the room or it may have already been singled out—it is the portrait. It has been identified. And it happens to have been knocked askew.
Thus with word choice and proper comma placement, the writer conveys very specific information.
How about the second sentences of each pair? This is a bit trickier. Not necessarily for the reader, who should pick up the nuances, but perhaps for the writer not sure how to write or punctuate what he needs to convey.
Let’s start with the second sentence first. It tells us that the narrator is ecstatic over the late snow. He then gives us more description of that snow, how it piled up in the street and reached over the tops of the cars. What’s important here, what’s essential, is the first part of the sentence. The second part, after the comma, is not essential to the thrust of the sentence. What’s essential is that the narrator is ecstatic over the late snow.
The comma and which tell us that what follows is nonessential. It may be interesting information, but the writer could have stopped the sentence at the comma and still have conveyed exactly what he needed to convey—I was ecstatic over the late snow.
The first sentence tells us there’s something essential in the information about how high the snow is going. It’s not only the snow that the narrator is ecstatic about. It’s the fact that it’s quickly covering the cars in the street. Cars won’t be able to move or maybe they won’t be able to be identified. Maybe one that’s out of place won’t be seen. Maybe the dent in the bumper or the body in the trunk won’t be noticed right away.
The possibilities will depend on the rest of the scene, but the way this is written lets the reader know there’s something more to the revelation than simple delight with snow; something’s going on. And the narrator is beyond pleased that the snow is, for the time being, hiding his secret from the world.
Again, we’ve got almost identical sentences, but the information presented is different. Punctuation and word choice do matter.
Note: Because so many writers have been encouraged to delete most uses of the word that, they sometimes use which when that is actually the proper and necessary word. It is okay to use that.
The use of who gives us the same opportunities, in terms of both meaning and potential problems, that that and which give us.
Who is used in place of which when people, rather than things, are involved. The first problem is that who is also used in place of that when people are involved.
So who is the word used in both essential and nonessential phrases and clauses. The question, then, becomes one about comma use. But the rules are the same. Non-essential phrases get commas; essential phrases don’t.
My youngest brother, who’s a Pisces, doesn’t know how to swim.
I’d hoped to contact the President, who had no personal cellphone, about opening an account for his family.
Matt told me about Amber, who’d been his girlfriend for eight years.
The youngest is the brother who doesn’t know how to swim.
I gave my cellphone to the senator who dropped his in the toilet.
Amber was the girl who’d been Matt’s girlfriend for eight years.
Note: Who is not always preceded by a comma. I see commas thrown in before who in many essential phrases—if the word, phrase, or clause is needed to identify the person, that information is essential and is not separated out by commas.
Are there other phrases, phrases that don’t begin with that, which, or who, that can be essential or nonessential, depending on the meaning? Of course. And that means you need to choose the proper punctuation to fit your meaning.
Participial phrases are often nonessential and thus often require commas.
The school kids, hoping to get down the mountain before the storm broke over them, took cover when lightning arced around them.
But a sentence such as this, with the participial phrase as a modifier identifying which school kids took cover—essential information in this case—doesn’t require commas—
The school kids hoping to get down the mountain took cover when lightning arced around them.
Also, while most dependent clauses introduced by a subordinating conjunction (as, after, although, because, once, until, when, while, etc.) that follow an independent clause are essential, some are nonessential and require commas. (See Commas with Subordinate Clauses.)
Alex stopped counting after twenty-five minutes.
Jane ran away, although her mother threatened her with punishment.
Tiny was six feet tall, whereas his brother was six seven.
The boys understood when I explained the house rules.
Some other words to be aware of when deciding essential or non-essential, comma or no comma—
I ate because I was hungry.
I hoped I was on the right road, because I was a dead man otherwise.
She was the woman whose son had been lost at the lake.
She was the woman seen wandering the streets at night, whose son had been lost at the lake.
Timmy followed the puppy as it raced through the field.
Timmy followed the puppy, as the kidnapper had intended for him to do.
Note: Remember that you can move most nonessential words or phrases around in a sentence or pluck them out and the sentence will still make sense and the meaning will not change. (Relative clauses beginning with who, whose, and which can be plucked from a sentence without changing the meaning, but can’t always be easily moved around.) When you move or remove essential phrases, however, you often create nonsensical sentences or change the meaning of the original.
So . . .
Because I was a dead man otherwise, I hoped I was on the right road.
I hoped, because I was a dead man otherwise, I was on the right road.
Seen wandering the streets at night, she was the woman whose son had been lost at the lake.
Timmy, as the kidnapper had intended for him to do, followed the puppy.
As the kidnapper had intended for him to do, Timmy followed the puppy.
Whose son was lost at the lake, she was the woman. X
For fun, a few more examples. Test yourself on the differences in meaning between the sentences in each pair.
The boys showed off the awards that they’d won.
The boys showed off the awards, which they’d won at the shooting range.
Rosella bought the donuts that were two days old.
Rosella bought the donuts, which were two days old.
She needed to return her books to the library that was just down the street.
She needed to return her books to the library, which was just down the street.
The sentences in each pair do have different meanings.
This one was a bit detailed, with specifics for word choice and punctuation. I hope the examples prove clear and understandable.
Use the rules to help you say exactly what you intend to, what you need to, as you craft your stories.
Write clear sentences.
Write great fiction.