What ELSE You Need to Know About Commas

Last week I discussed the first four of nine rules for commas. This week we’ll cover rules five through nine. By way of review, here are the nine rules:

Comma Rules

1. Use a comma before the coordinating conjunction joining two independent clauses in a compound sentence.
2. Use a comma after an introductory word, phrase, or clause that comes before the main clause.
3. Use a comma between each of three or more items in a series.
4. Use commas to separate two or more coordinate adjectives that modify the same noun.
5. Use commas to set off “non-restrictive” modifying elements.
6. Use commas to set off interrupters and parenthetical elements.
7. Use a comma to set off nouns of direct address.
8. Use a comma to set off verbs of attribution in dialogue.
9. Use a comma near the end of a sentence to separate contrasted coordinate elements or to indicate a distinct pause or shift.

If you missed last week’s letter, here it is. Now, on to Comma Rules 5-9.

Comma Rule 5: Non-Restrictive Modifying Elements

Use commas to set off “non-restrictive” modifying elements. When you learned this rule, you may have learned it in terms of “essential” and “non-essential” elements. That’s the way I first learned it: Use commas to set off “non-essential” words, phrases, and clauses in a sentence. In this formulation, an essential element changes the essential meaning of the sentence, and a non-essential element doesn’t.

I have quit using the terms “essential” and “non-essential.” They too easily suggest “important” and “less important” or, perhaps, “adding meaning” and “not adding meaning.” Any word, phrase, or clause you add to a sentence ought to add meaning. Instead, as whether a modifying element adds meaning by narrowing or by expanding. A modifier that adds meaning by narrowing is restrictive. A modifier that adds meaning by expanding is non-restrictive.

The following two sentences (which tell a mostly true story that you can read about here) illustrate the difference between restrictive and non-restrictive modifiers:  

1. The playwright Samuel Beckett gave young Andre the Giant a ride to school.
2. Samuel Beckett, the playwright, gave young Andre the Giant a ride to school.

These sentences are nearly identical. So why does Sentence 2 have commas but not Sentence 1?

Each of these sentences has an appositive—that is, a noun or noun phrase that renames the noun that immediately precedes it. In Sentence 1, Samuel Beckett is an appositive renaming playwright. In Sentence 2, playwright is an appositive renaming Samuel Beckett.

In Sentence 1, the appositive Samuel Beckett is restrictive: it narrows the category “playwright” down to the specific person Samuel Beckett. Therefore, there are no commas.

Now look again at Sentence 2:  

• Samuel Beckett, the playwright, gave young Andre the Giant a ride to school.

In this case, the commas around the appositive phrase the playwright signal that this is bonus information. The subject Samuel Beckett is as specific as you can get, so any additional information will be non-restrictive, adding meaning by expanding, not by narrowing. The appositive may be helpful to the reader who can’t put her finger on who Samuel Beckett is, but to leave it out doesn’t change the essential meaning of the sentence.

Look what happens when you remove the appositives from the two sentences. They look a lot less identical:

1. The playwright gave young Andre the Giant a ride to school.
2. Samuel Beckett gave young Andre the Giant a ride to school.

That shows even more clearly the difference between narrowing (essential) modifiers and expanding (non-essential) modifiers. Some random playwright giving Andre the Giant a ride to school is interesting enough, but the real heart of the sentence is the image of the black-turtleneck-clad Samuel Beckett, icon of the Theatre of the Absurd, trundling Andre the Giant to school.

The principle applies to all types of modifiers, not just appositives:

• Samuel Beckett, driving a flatbed truck, drove young Andre the Giant a ride to school.
• Samuel Beckett, who had a house in Andre the Giant’s hometown, gave young Andre a ride to school.
• Samuel Beckett, not knowing he was in the presence of greatness, gave young Andre the Giant a ride to school.

There’s no need to wrap yourself around the question of whether the elements driving a flatbed truck, who had a house in Andre the Giant’s hometown, or not knowing he was in the presence of greatness change the essential meaning of the sentence. Just think in terms of narrowing and expanding. None of these elements narrow Samuel Beckett to anything more specific, so all should be set off by commas.

Proper nouns make things quite easy on this count. A proper noun, by definition, has already narrowed things down from a category to a specific instance of that category. So be ready with your commas when you shift from common nouns to proper nouns:

• I like living in a state where there is no income tax.
• I like living in Tennessee, where there is no income tax.

On rare occasions you may use an essential clause to modify a proper noun, if you are trying to distinguish between more than one thing with the same name. If you think your reader might mistake playwright Samuel Beckett for some other Samuel Beckett, you might write something like, 

• The Samuel Beckett who wrote Waiting for Godot gave young Andre the Giant a ride to school.

But this is an exception precisely because the proper noun Samuel Beckett is operating here not as a proper noun, but as a small category that needs to be narrowed down further.

When you are dealing with elements that modify common nouns rather than proper nouns, the same principle applies: does the modifier add meaning by moving from more general to more specific, or by providing bonus information? Consider these two sentences:

1. Cilantro that tastes like soap grosses me out.
2. Cilantro, which tastes like soap, grosses me out.

Which of these sentences is correctly punctuated? My friend Russ Ramsey thinks all cilantro tastes like soap. It’s a genetic thing, apparently. So for Russ, the clause which tastes like soap doesn’t narrow anything down. Sentence 2 communicates Russ’s position on cilantro. The clause which tastes like soap is explanatory information, bonus information, so it should be set off by commas.

You and I, however, like cilantro. Still, we would be grossed out if ever we ran across some cilantro that tasted like soap. Sentence 1 communicates this position. The absence of commas communicates that the clause that tastes like soap is essential, narrowing the category down from cilantro to a specific kind of cilantro.

You will have also noticed that the non-restrictive clause “that tastes like soap” starts with that, whereas the restrictive clause “which tastes like soap” starts with which. When deciding whether or not to set off an adjective clause with commas, that relative pronoun is another helpful clue.

Comma Rule 6: Interrupters and Parenthetical Elements

Set off “interrupters” or parenthetical elements with commas. An interrupter is an extra word or phrase that interrupts the logical and grammatical flow of a sentence. A parenthetical element is a phrase or clause that you could remove completely from a sentence without really affecting the meaning of the sentence; it is an element that you might set off with parentheses—or possibly with dashes.

Both interrupters and parenthetical elements are grammatically independent from the sentences they inhabit. To put it another way, in a sentence diagram, there would be no good place to put an interrupter or parenthetical element. Consider the following sentence, in which “sadly” is an interrupter:

• The Tennessee Vols, sadly, beat the Vanderbilt Commodores in football.

Sadly is an adverb here, but it doesn’t modify the verb beat. The Vols weren’t feeling sad as they beat the Commodores. And while the Commodores, no doubt, were sad about getting beaten by the Vols, sadly is not intended to describe their feelings either. Rather, sadly describes or modifies the sentence as a whole. You might say sadly describes the feelings of the speaker, who needs to toughen up if he’s going to be a fan of Vanderbilt’s football team.

In this sentence, a parenthetical element is set off by commas:

• John Barber has a taste for cheese coffee,* if taste is the word I’m looking for.

That clause, if taste is the word I’m looking for, pulls out of the sentence in order to comment on the sentence. But, again, if you were to diagram the sentence, there would be no good place on the diagram for that clause. It is parenthetical and should be separated from the rest of the sentence by a comma.

*I know this sounds made up, but John Barber actually does put cheese in his coffee.

Comma Rule 7: Nouns of Direct Address

Use commas to set off nouns of direct address. This one is relatively straightforward. A noun of direct address identifies the person to whom an utterance is directed. It can be a name or a common noun, and it can come at the beginning, the middle, or the end of a sentence. Here are some examples:

• Get thee behind me, Satan.
• Tell me, friend, what you need.
• John Barber, you will rue this day.
• Here, kitty, kitty.

Comma Rule 8: Verbs of Attribution

When you use a verb of attribution before or after a quotation, use a comma to separate the attribution from the utterance. A verb of attribution is a verb like “said” or “asked” that is used to identify the speaker.

• Wendell said, “This book changed my life.”
• “You’ve got to be kidding,” Martha said.

An exception is when the utterance ends in a question mark or exclamation mark and the attribution comes after the utterance. (Note, however, that you don’t capitalize the attribution):

• “Is this the right address?” the mailman asked.

It is common to identify the speaker in dialogue not with a verb of attribution, but by showing the speaker doing some gesture besides speaking. When you aren’t using a verb of attribution, don’t use a comma. Rather, treat the utterance as its own sentence (or sentences) with its own end-punctuation. 

• “This book changed my life.” Wendell stroked the cover lovingly.
• The mailman leaned out of his truck. “Is this the right address?”

And remember, the punctuation at the end of an utterance, whether it’s a comma or end-punctuation, always goes inside the quotation marks.

Comma Rule 9: Pause or shift near the end of a sentence

Finally, use a comma near the end of a sentence to separate contrasted coordinate elements or to indicate a distinct pause or shift. Contrasted coordinate elements often take the form not x, but y, like so:

• She wanted not pie, but oysters.
• A restrictive modifier adds meaning not by expanding, but by narrowing.
• The proper noun Samuel Beckett is operating here not as a proper noun, but as a small category that needs to be narrowed down further.

Sometimes contrasted coordinate elements are connected by not (and a comma):

• He was merely inexperienced, not stupid.

Other times, a comma indicates a shift toward the end of a sentence:

• The chimp seemed reflective, almost human.
• You’re one of his friends, aren’t you?

Occasionally (but only occasionally) you can use a comma for clarification in the way that a pause in speaking would distinguish different grammatical chunks of a sentence. That is to say, sometimes a comma helps make a sentence more readable even if no other rule applies. In the following sentence from earlier in this letter, a comma indicates that kind of pause:

• On rare occasions you may use an essential clause to modify a proper noun, if you are trying to distinguish between more than one thing with the same name.

This “distinct pause” comma can be a slippery slope. Use it sparingly and only when you are sure the sentence is less clear without it; otherwise you’ll start inserting unnecessary commas everywhere you might pause in speech, and that’s not good for anybody.

So those are the comma rules. If you learn them and apply them, you will get your commas right almost all the time. Comma usage isn’t really a matter of style. There is room for interpretation in the application of these rules, but not as much as you might think.

Hope that helps.