The Comma “,”

by Dustin Pascoe

Usually accepted as the most confusing of all punctuation marks, there are about 17 rules guiding the use of commas, some of them apparently contradictory. For most common writing purposes, there are eight or nine major occasions to remember. Only some of these rules will actually obscure meaning when followed incorrectly, but the rest are no less important for that.

One of the key myths to dispel about commas is that they indicate breath stops or pauses, but they do not. Commas are not “stage directions” or instructions in how to “say” the text. Commas exist to separate units of meaning – or to make the connections between units clear to the reader. In short, they are grammatical, not “mood-based.”

So how can commas be used?

a. In specific dates:

On July 4, 1776, the Continental Congress signed the Declaration of Independence.

Notice that the commas go before and after the year in a specific date. If you wrote “in the summer of 1776”, that year would not need commas because it’s not a specific date.

b. In address/places:

The school is at 101 College Avenue, Moberly, Missouri, if you want to send them mail.

Here, the commas are used to separate the street from the city and the city from the state. The names of states are like years in dates: if it is specific, commas will be needed before and after: “In Seattle, Washington, . . .” You do not need commas in a usage like “We like to go skiing in Washington.”

c. After an introductory phrase or clause:

If you use commas incorrectly, your readers may not take you seriously.

An “introductory phrase or clause” is the kind of thing that often begins with a preposition (like “if ” or “on” or “at”) or a subordinating word like “when” (“When you misuse commas, your readers will not take you seriously.”) or “while” (“While Rome burned, Nero fiddled.”).

d. With coordinating conjunctions:

Comma rules can be difficult to learn, but they are important to clear writing.

A “coordinating conjunction” means using one of seven words (for, and, nor, but, or, yet, so) to join together two (or more) complete thoughts (sentences). Notice how in the example both of the ideas on either side of the comma could stand alone as sentences. A comma is used before the conjunction in that instance.

e. When there are more than two items in a list:

To really appreciate a movie, you need popcorn, candy, a drink, a date, and lots of money to burn.

When using a list, the “Oxford” comma before the last “and” should be included. You do not need a comma in a two-item list (“I’m going to take Bernie and Paul.”)

f. To set off non-essential or appositive elements in a sentence:

Soccer, the most popular sport in the world, is a very simple game.

“Non-essential” means that the word, phrase, or clause is not necessary to the grammar of the sentence: take it out and the sentence reads the same (“Soccer is a very simple game.”). An “appositive” renames the preceding noun (“Detroit, the Motor City, has emerged from bankruptcy proceedings.”) This rule also applies for interrupter words that just comment on the sentence (“He did, however, confess to several other minor crimes” or “She was really surprised, obviously, to find she’d been living with such a disreputable character.”).

Some writers treat non-essential elements and appositives as different things, which explains the hedging about “eight or nine” rules at the top of this section. That comma before “which,” by the way, is to separate a non-essential element. The commas around “by the way” are for an interrupter.

g. To separate coordinate adjectives:

Music critics have often praised the album’s simple, spare instrumentation.

Both of the adjectives modify “instrumentation”. You would not write, “It was a shaggy, German shepherd” because “shaggy” and “German” are not both modifying “shepherd,” but only “shaggy” was the adjective. Yet, you could write, “It was a shaggy, brown dog” where both “shaggy” and “brown” are both telling the readers something about the dog.

h. To introduce quoted speech:

President Kennedy said, “Ask not what your country can do for you” in one of his more famous speeches.

This rule asks you to treat the phrase or clause that explains the origin of the quote as a kind of separate element, so the comma would occur no matter where the quote occurred in the sentence (“‘Ask not what your country can do for you,’ said President Kennedy in one of his more famous speeches.” Or “In one of his more famous speeches, President Kennedy said, ‘Ask not what your country can do for you’.”)

Common misuses of commas:

Do not use a comma between the subject and verb:

I , threw the ball through the window.

Do not use a comma after the coordinating conjunction:

You did that, and , she got really upset later.

Do not use a comma when the clauses are not both complete sentences:

I grade the essays carefully , and then give all As.

Do not use commas when the information is grammatically necessary:

All the athletes , who have tested positive , must re-test.

Do not use commas to introduce a list:

Remember to take , a lamp, rope, duct tape, and a knife.