One of the Most Useful Marks of Punctuation is the Comma

It is also one of the most misused and misunderstood marks...

How confusing is it to use a period? Or for that matter a question mark? Or even an exclamation point? I think we learn about these three marks of punctuation in grade school, because they're easy to understand. A period comes at the end of a sentence. A question mark is used when the sentence is in the form of a question. An exclamation point is used to show excitement, shock, or any high-octane emotion.

And even though bad writers might not be sure exactly what constitutes a sentence, they're sure that a period needs to follow it. Bad writers also overuse the exclamation point! I mean, really!! But that's not my concern, here.

Nor is my concern with the semicolon, ellipses, en- and em-dashes, double or single quotation marks, or parentheses—just the important, lowly, misunderstood, and misused comma.

So, just what is a comma? Unlike the period, a comma is only used as an internal mark of punctuation in a sentence. It either links two or more items in a sentence or separates them. Poets might insist that a comma is meant to show a pause before continuing. That's a rather poetic way of explaining what a comma does. But that might be a good test of whether a comma should be used or not. Except when it isn't a good test, as we will see in the examples below. We cannot depend on using it to show a pause.

But some writers insist on this pause in a sentence that begins with "but" or "and" and place the comma after such conjunctions. A dramatic reading would actually create a slight pause after "but."

Example: But, he never looked back.

This is one of the ways the comma is misused. But to make this point also misunderstood, here is an example of when a comma should follow the conjunction:

But, because there were tears in his eyes, he never looked back.

Note that in the first example, what follows "but" is a clause and the integral part of the sentence. In the second example, what follows "but" is a phrase or added information that might clarify the sentence, but the phrase could be left out without doing harm to the integrity of the sentence. Also note that there are actually two commas in the second example, because like parentheses, the two commas close off the phrase, separating it from other parts in the sentence.

One of the conventions, of course, is that if a sentence can be understood without using the commas the conventional rule of thumb is to leave them out, and the mantra goes up across the English classrooms, "When in doubt, leave it out."

Some writers want there to be black and white rules for the use of commas, as there seems to be for using periods and question marks, but the comma is much more complex than that. Here's a quick summary of the use of the comma before we continue illustrating such uses:

1. A comma is only used within a sentence and not as an end mark.
2. A comma either links two or more items in a sentence or separates them.
3. A comma is usually not used following "but" or "and" when they are used to begin a sentence.
4. Commas come in pairs when they are used to separate a phrase or interrupting idea from the rest of the sentence—if the phrase can be lifted out of the sentence without affecting the integrity of the sentence.

These are really the simple "rules" for using commas. But drat all those style guides that publishers insist on using when they publish a book or a magazine article. There's a whole other universe of "rules" for using commas writers hardly ever think about, and for your sake I'm not going to get into those esoteric uses, just yet.

But here is a hint. There is an ongoing debate about using a comma before "and" in a series. This is called the "Oxford" comma, or it is sometimes called the "serial" comma. The Chicago Manual of Style sides with the debate to use the comma before "and" in a series, whereas The Associated Press style guide insists that it is not needed. As you can see, this debate is about a lesser known use of the comma that will give some writers a headache.

Next,  let's take a look at how the use of a comma can change the entire meaning of a sentence...really!

Hide the cows outside.

Isn't this unambiguous? We are being told to conceal the cows outside. But let's add a comma (and another mark of punctuation) to this simple sentence and see what happens.

Hide, the cow's outside. Shoes are made of leather. Leather is, for lack of a better explanation, the cow's hide, which when tanned becomes leather.

A woman without her man is useless. Yeah, besides being sexist, it's pretty clear what this means. Let's just stretch the sentence a little (however badly written) to show the utter power of the comma in changing the meaning of the sentence:

A woman, without her, man is useless.

Now that you're an expert on the basic uses of a comma, let's appear to contradict the "rule" that says a comma is only used within a sentence and not as an end mark.

"Let me have the red scarf," he said to the clerk.
In this sentence it only appears that the comma that follows "scarf" comes at the end of the sentence, "Let me have the red scarf." But in actuality the whole sentence includes what comes after the quoted material. The single idea (the sentence) is that a man tells the clerk which scarf he wants. It doesn't matter if we put quotation marks around part of the sentence. Conventional use of the dialog tag, like "He said," cannot stand on its own as a single idea, so we attach it to the dialog as part of the whole sentence.

In a later post, I will revisit the comma to delve into the more esoteric uses and abuses of this extraordinary mark of punctuation. We might call it The Battle of the Style Guides.