I have not before found a subject that created so much controversy as this one. Let’s face it; the comma is a simple piece of punctuation — it separates things.
Why, then, are there so many arguments over its usage?
As an editor, I’m always battling writers about using too many or too few commas. I don’t know why because it’s not that difficult. That said, sit back and pull your seatbelt tight because it’s going to be a long and bumpy ride.
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Abbreviated Table of Contents
Noun of Address
Conjunctive Adverbs and Transitional Expressions/Phrases
There are a number of usages that are accepted by nearly all references.
Use commas after the street address and city in an address.
My address is 5468 15th Street, San Bernardino, CA 92410
(Note: there is no comma after the state and that is not my real address.)
Use a comma after the greeting in personal letters.
Dear Aunt Sue,
Note that in business you would use a colon.
Dear Mrs. Maxwell:
Use a comma after the complimentary close in any correspondence.
Very Truly Yours,
Use commas after the day and year in a date.
I was born January 7, 1947, and haven’t died yet.
(Note: there are some references that say the comma after the year is unnecessary.)
The military, some businesses, the scientific community, and many legal papers use the Modern Language Association of America Manual of Style which puts the date in a different order and no commas are used.
I was born 7 January 1947 and haven’t died yet.
I was born 7 Jan 47 and haven’t died yet.
In American English, we use commas to separate each group of three digits when writing numerals.
In my tutorial on numbers, I mentioned that I found some arguments that said you don’t use a comma until you have five digits (2569, but 12,569) although that is rare.
There are times you might use a comma to avoid confusion in a sentence. (You might consider that it would be better to reword your sentence.)
Sam rushed in, in a flurry of shouting and screaming.
Like Sam, Sue is a good person.
I have three sons. If I’m talking about one of them and include his name as a means of identity, it is not parenthetical. If I add some additional information that specifies whom I’m discussing, the name becomes parenthetical.
My son Patrick lives in Arkansas.
My oldest son, Greg, lives in SoCal.
In the first sentence, I have to include his name so the reader will know which son I’m discussing. In the second sentence, I already said “my oldest son” and I only have one of those; thus, his name is parenthetical.
Look at these two sentences.
The lawnmower that is broken is in the garage.
The lawnmower, which is broken, is in the garage.
In the first sentence, there may be more than one lawnmower, but one of them is broken and it is in the garage.
In the second sentence, there is only one lawnmower, and it’s located in the garage.
Be very careful using which. Most of the time, whatever follows it is parenthetical and, possibly, not necessary to the sentence.
I used this example in my tutorial on semicolons so I’ll repeat it here. An independent clause is a group of words that can stand alone as a sentence.
This is a complete sentence. This is another complete sentence.
There are three ways to connect these two sentences into one correctly. First is by using a coordinating conjunction.
This is a complete sentence and this is another complete sentence.
The second way — informal and found more in creative writing — is to use a dash.
This is a complete sentence — this is another complete sentence.
The third way is to use a semicolon.
This is a complete sentence; this is another complete sentence.
A comma splice occurs when you use a comma to combine two independent clauses.
This is a complete sentence, this is another complete sentence.
Style guides, teachers, editors, and writing coaches constantly harp on not using a comma splice. But…
There are places for the comma splice. One such place is when short independent clauses are joined together. Consider one of the most famous that is shown in many reference sources. I came, I saw, I conquered. I can’t imagine Julius Caesar’s publisher saying, “No, you can’t write it like that. That’s a comma splice.”
Another time a comma splice is acceptable is when you want to show a contrast between two fairly short independent clauses. As you can see from the last example, the term fairly short can be interpreted somewhat loosely.
That is my wife, this is my mistress.
I’m not visiting, I live here.
I won’t be visiting Oregon on my vacation this year, I’ll be going to Arizona.
One last time a comma splice can be used is when you append a short question.
You finished high school, didn’t you?
You’ve seen that movie, haven’t you?
I covered this in Punctuation and Dialogue — A Tutorial, but I’ll recap the portions dealing with a comma.
In dialogue, you separate the intro from the dialogue with a comma.
Sue said, “Get out of here.”
Sue said, “Get out of here.” She paused and then added, “Unless you don’t want to.”
“Get out of here,” Sue said.
“Get out of here,” Sue said, “unless you don’t want to.”
Depending on the point of view, thoughts can be handled similarly, except they’re put in italics.
Sue thought, Get out of here.
Sue thought, Get out of here. She paused and then added, Unless you don’t want to.
Get out of here, Sue thought.
Get out of here, Sue thought, unless you don’t want to.
A comma is also used to separate items in a list.
I bought eggs, milk, and bread.
Notice the comma before and; that is called a serial comma. Many major style guides say to use it (such as the Chicago Manual of Style). Others eschew its usage (such as the AP Style Guide).
An interjection is a word or phrase that interrupts the sentence and has no real grammatical connection. It can be either sharp or mild. If sharp, it is usually set off with an exclamation point.
Ugh! That’s just plain gross.
Ouch! What are you doing to me?
If it’s mild it can be set off with a comma.
Alas, this just won’t work.
Oh, you startled me.
If you have two interjections together, it’s a toss-up whether you separate them with commas or not. Both of the following examples can be correct.
Oh, oh, Sam, what have you done? (This seems to be preferred in most guides.)
Oh oh, Sam, what have you done? (Note the difference when reading this line.)
Let me get silly for a moment and give you an extended interjection.
Oh, Sam, oh, Baby, oh, God, oh, oh, Sam, what have you done, oh?
Yes, I know what that brings to mind, but it is, grammatically, correct.
Keep in mind that an interjection is anything that interrupts the flow of the sentence and can be nearly any part of speech.
Sam! What are you doing?
Walking? You were just walking?
Pretty, I guess that’s what you thought of her.
As is the case in much of the English language there are words that serve different purposes. Too is one such word. It is an adverb, but can serve as an interjection. There is a concerted effort by many writers and grammarians to eliminate the comma before a final too in a sentence.
Did you do it, too? (The old way.)
Did you do it too? (The new way.)
Noun of Address
The noun (or pronoun) of address is the person to whom a character is speaking. A noun of address is used only in dialogue or thoughts and is always set off with commas.
“Come on, Sue, we have to be going,” Sam said.
“Sue, we have to be going,” Sam said.
Sam said, “We have to be going, Sue.”
Come on, Sue, we have to be going, Sam thought.
Keep in mind that it can be more than just a single noun.
“Get over here, you imbecile,” Sam said.
“Okay, you dummy, what’s your excuse this time?” Sam asked.
“Okay, you dumb, worthless, piece of trash, what’s your excuse this time?” Sam asked.
“Let me see if I have this right, son of Sam,” Sue said.
When you have two or more adjectives that modify the same noun equally, you separate them with a comma. (A couple of Web sites recommend testing it by substituting and in place of the comma and, if it makes sense, use a comma.)
Sam had thick, curly hair.
Sam had thick, curly, blond hair.
Sam had thick, curly, light-blond hair.
Note in the last example the use of light-blond. In this case light is an adjective used to modify an adjective (blond) and, together, they modify a noun (hair). In such a case, you hyphenate them to form a compound adjective.
I’ll get off the subject a bit to discuss those examples. Preferences change over the years and blonde and blond is one such case. Most dictionaries and style guides now say that blond refers to a man and blonde refers to a woman. In the case of a person whose gender is not specified, it’s a tossup.
Sam had blond hair.
Sue had blonde hair.
The criminal had blond hair.
– or -
The criminal had blonde hair.
Here’s an interesting thought for you. In creative writing we occasionally want to mislead our readers a bit to add some question to whatever we’re doing. Think about writing a mystery and your antagonist is a man; you might put in the statement, “The criminal had blonde hair.” That might lead your reader to think the antagonist was a woman. Is that honest? No, probably not, but it’s a good tool for us.
I mentioned these in an earlier tutorial and I’ll recap that here. Coordinating conjunctions are used to connect things. Whether you use a comma or not with one of them depends on the structure of the sentence. There are six that are always listed as coordinating conjunctions: and, nor, but, or, yet, and so. The common memory aid is ANBOYS.
Many people include for in that list (making the memory aid FANBOYS). Here’s where I add to my enemies list because I think of for as equating to because, which is a subordinating conjunction. Your choice which way you want to go.
Whichever way you go you have to agree that they connect things.
Sam did it and Sue did too.
Sam didn’t go nor did Sue follow.
Sam did it but Sue didn’t.
Sam did it or Sue did it.
Sam is good yet Sue is better.
Sam is good so Sue tries harder.
I found several sites that recommended a comma before a coordinating conjunction. They said that “This is a complete sentence, and this is another complete sentence” is the correct way to punctuate that sentence.
They then went on to point out that modern writing was getting away from “too much punctuation” and was leaning toward not having the comma before the conjunction.
If you have a series of nouns/phrases separated with coordinating conjunctions, you do NOT use a comma.
Sam and Sue and Joe all went to church.
Cleaning the cat box and walking the dog and watering the plants took nearly all day.
Please note that, while grammatically correct, these sentences could have been written better using commas.
Sam, Sue, and Joe all went to church.
Cleaning the cat box, walking the dog, and watering the plants took nearly all day.
These are some of the hardest to figure out because of how you word the sentence. A subordinating conjunction introduces a subordinate or dependent clause and makes the clause dependent on the rest of the sentence. The problem is in the sentence structure because that subordinate clause might be, in its own right, an independent clause, but it depends on the rest of the sentence for its meaning. You, often, don’t use a comma to separate the clauses and, other times, you do use a comma.
The most common subordinating conjunctions are: after, although, as, as if, as long as, as though, because, before, even if, even though, if, if only, in order that, now that, once, rather than, since, so that, than, that, though, till, unless, until, when, whenever, where, whereas, wherever, and while
Basically, if you introduce the sentence with the subordinating conjunction, you use a comma at the end of the subordinate clause. If you put the subordinate clause at the end, you normally don’t use a comma.
Because he was late, Sam was fined.
Sam was fined because he was late.
Even though Sam was late, he kept his job.
Sam kept his job even though he was late.
Unless we change, we’re lost.
We’re lost unless we change.
Conjunctive Adverbs and Transitional Expressions/Phrases
As the name implies, a conjunctive adverb is an adverb used as a conjunction. The most common are: namely, however, therefore, consequently, thus, hence, meanwhile, moreover, nevertheless, and otherwise.
Transitional Expressions/Phrases are short phrases used as conjunctions. The most common are: that is, i.e., for example, e.g., for instance, in addition, in other words, and in fact.
These components act the same as conjunctions except they are followed by a comma. If you join two independent clauses with a conjunctive adverb or transitional expression/phrase, you place a semicolon before the component and a comma after.
I like girls; however, they don’t always return the feeling.
The bus was delayed by the drivers’ strike; consequently, I was late.
Sue didn’t enjoy Sam’s company; in other words, she didn’t like having Sam around.
When camping, I always take certain things; for example, I carry matches, water, and toilet paper.
Now that we’ve got all the rules down, it’s time to learn when and how to break them.
I alluded to something in a few statements above; we use a comma to interrupt the flow of a sentence. Here’s something that is not taught in English classes: when we’re writing, we can stick in a comma wherever we want to slow down the reader.
What? Yes, the comma has specific purposes in grammar, but when someone is reading our work, a comma causes them to pause. Look at the following samples.
Sam did this. Sue did that.
Sam did this and Sue did that.
Sam did this but Sue did that.
The period in the first sample equates to a full stop. It would be read as:
Sam did this [STOP, TAKE A BREATH, AND THEN CONTINUE] Sue did that.
The other two samples would be read straight through without interruption. But, if we wanted the reader to pause for some reason, we could put in a comma.
[Written as] Sam did this, and Sue did that.
[Read as] Sam did this [PAUSE] and Sue did that.
[Written as] Sam did this, but Sue did that.
[Read as] Sam did this [PAUSE] but Sue did that.
When you’re writing and want to slow things down, keep in mind that a period equates to a [FULL STOP] for the reader; a comma equates to a [PAUSE]; and a semicolon equates to a [PAUSE LONGER THAN A COMMA BUT LESS THAN A PERIOD].
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As always, I’ll mention that this is not an English course; it is designed as a reminder for writers who may have forgotten some things over the years. I have left out definitions of some of the basic terms and I’m thinking about another tutorial about that.
I research dictionaries, style guides, and Web sites to come up with as many arguments as I can. Then I combine all the information and try to present a balanced viewpoint.
I constantly stress two things in these tutorials:
1. If you have a preferred style guide — use it.
2. Always do things the same way.
If you find any errors or believe I left out some argument that’s important, please include it in a comment and I’ll make any corrections necessary.
This is one of a series of tutorials and you can read the others here.
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Besides the many great comments I received from writers, I want to thank Kimberly Blackadar for an excellent discussion and a lot of help with this topic.