Punctuation can get confusing, but when used well, it’s a guide to meaning. Those subtle marks on the page give the reader plenty of context about how the words and ideas fit together. Today’s blog post will help you figure out whether to use commas around certain phrases, and which word choice is best, based on what information your sentence contains.
My mom’s sister, Aunt Vivian, called today with some surprising news.
Or is it
My mom’s sister Aunt Vivian called today with some surprising news.
?
It depends on context: specifically, on how many sisters your mom has.
Nonessential (even parenthetical) information
If she and Vivian are the only two daughters in their family, then “Aunt Vivian” is equivalent to “My mom’s sister.” To say one is to say the other. In this case, the commas around “Aunt Vivian” are needed – they’re necessary because “Aunt Vivian” isn’t necessary. The sentence would mean the same thing as “My mom’s sister called today.”
The commas mark “Aunt Vivian” as nonessential.
It could help here to think of another form of punctuation we often use to mark off nonessential information: the parentheses.
You don’t want to overuse parentheses (I’m often in danger of doing so!). They can be a bit distracting. But they’re helpful when you want to fit in information that isn’t required to make sense of your writing but is interesting or informative for your reader. When words are in parentheses, it’s a sign they can be taken out and the sentence will still make sense.
My mom’s sister (Aunt Vivian) called today with some surprising information.
See where the parentheses go? And how there are two of them, opening and closing the little aside? The commas setting off your nonessential information work the same way. You need two: don’t write My mom’s sister, Aunt Vivian called today.
Essential information
However, if your mother has several sisters, then “Aunt Vivian” is essential information. The reader needs it to make sense of your sentence and understand which woman called. In that case, you don’t want to set it off in parentheses or in commas:
My mom’s sister Aunt Vivian called today with some surprising news.
Appositives, the descriptive restatements
However, even if your mom has several sisters, I would write:
Aunt Vivian, my mom’s sister, called today with some surprising news.
That’s because once you’ve identified Aunt Vivian, the detail of which parent she’s a sibling of isn’t so essential to the sentence. Saying My mom’s sister called today would raise the question Which of your mom’s sisters? But Aunt Vivian called today already makes clear exactly who called. “My mom’s sister” is some added garnish describing Vivian. It’s not required.
Specifically, “my mom’s sister” is an appositive, a noun that accompanies another noun to further describe or identify it.
Abraham Lincoln, the sixteenth president,
and
Alexander the Great, a talented twenty-something soldier,
are two more examples of appositives. So is the header of this section.
Appositives can be either essential or nonessential. In my mom’s sister Aunt Vivian, “my mom’s sister” is the appositive for Vivian even if Vivian is one of several sisters. So knowing this term isn’t, in itself, going to help you figure out whether to use commas. But it can help you identify what certain words and phrases are doing, and that can be helpful and interesting (at least if you’re a word nerd like me, Therese Arkenberg, freelance editor and writer – to give you some more appositives).
Essential = restrictive and nonessential = nonrestrictive
Two more bits of vocabulary, for those of you who enjoy such things: another word for essential is restrictive and another word for nonessential is nonrestrictive. You’ll sometimes see those terms in grammar discussions, and they’re referring to the same kind of distinction.
And the essential/nonessential distinction, aka the restrictive/nonrestrictive distinction, is also used to determine if you should say “that” or “which.”
(Notice how the “aka” phrase is in commas, and could be put in parentheses or removed from the sentence entirely? You’ve got an eye for the essential and nonessential information and how punctuation works around it!)
“That” or “Which”?
In practice, people aren’t always particular about this, especially in everyday conversation and conversational writing. But when you want to be polished and correct:
That goes with essential or restrictive information. Which goes with nonessential or nonrestrictive phrases.
Another way to put it: if it’s following a comma, use which.
The rose bush that blooms early is my favorite.
This sentence communicates that, among several rose bushes in the garden, I particularly like this one because it blooms early.
The rose bush, which blooms early, is my favorite.
In contrast, this sentence seems to say that the garden has several plants, but perhaps only one rose bush, and it’s my favorite because it’s a rose or perhaps for some other reason I haven’t stated in this sentence. The fact that it blooms early is an interesting characteristic, but not an essential distinguishing characteristic. I could have said The rose bush is my favorite and you’d get the same idea.
“That” or “Who”?
One last tip: “that” and “who” can both be used to attach information about a noun.
The author who finishes their second draft early is my favorite could also be The author that finishes their second draft early is my favorite.
But in general, use “who” to refer to people, not “that.” It’s more polite.
This isn’t to say we should run people that say “that” out of town. It’s usually not intentionally offensive, and it still makes sense. As a further rule of thumb, I find using “who” over “that” is most important when the phrase is more specific or about a heavier topic. For instance,
Writers that have finished the first draft of a novel are justifiably proud
is a pretty nice sentence and I don’t think any first-draft finishers would feel slighted by it (at least I hope not!).
Writers who have finished the first draft of a novel are justifiably proud
is a bit warmer and more strictly correct, though, and it could be useful to get in the habit of saying it so you also use “who” when it really matters.
If I were to point across the room at you and refer to The person [who/that] is reading my blog post right now, I expect you would feel better if I said “who.” Once you overcome the surprise of me being in the same room, of course. I’m singling you out so personally that it seems I ought to acknowledge you’re a person, not a rose bush (however well-liked).
And when it comes to serious topics:
Employees who spoke about being harassed by the CEO were fired
sounds better than Employees that spoke… would. The heavier, more sensitive topic benefits from the warmer and more unambiguously respectful language.
The word makes a small difference, but even small differences add up. After all, we’ve just seen that adding or omitting two commas can change the number of sisters in your mother’s family!