Rhetoric Rant - The Third Installment

Just so you know, this post is the result of a direct request from my friend Rachael, so I'm not sure it qualifies as a true "rant." My other two "rant" posts, here and here, sprang from my immense frustration over some grammatical error that I'd witnessed all too often in the recent past. I was actually considering doing a post on apostrophes next because they are constantly misused, but Rachael requested a post on commas, and I surely won't ignore an actual request from a reader. So here goes...

First and probably most important, you must ignore some erroneous babble you might have heard in the past from well-intended but sadly mistaken English teachers who told you to use a comma whenever you just happen to feel like pausing or taking a breath. Let us be crystal clear about this: commas have nothing to do with respiration! Nothing.

Whew. Now that we've settled that, we can move on. The reason commas are tricky is that there are certain grammatical constructions that require commas, other grammatical constructions that prohibit them, and still other grammatical constructions in which commas are optional. I apologize for this. I ask you not to kill the messenger. I only report the rules; I did not create them (even though my last name is Webster). Let's deal with each category separately. I won't have time or space to cover every single possible use of the comma, but if we deal with the most common situations, we'll know what to do nearly all the time. Moreover, I will leave out discussion of the ridiculously obvious situations (between cities and states in addresses, between the day and year in dates, etc.) because everyone knows about those, right?

Category #1 - Constructions that require a comma
1. Use a comma following two prepositional phrases that begin a sentence:
On hot summer days in July, I love to go swimming.

2. Use a comma following a coordinating conjunction (for, and, nor, but, or, yet, so) if the conjunction divides two independent clauses (complete sentences):
I got paid today, and I can't wait to go shopping.

3. Use commas to set apart non-essential elements in a sentence:
My friend, who has three young children, is coming to visit soon. (It might be nice to know that this friend has three young children, but that information is not necessary to show the reader which friend I'm talking about. Therefore it is considered non-essential and must be set apart with commas).

4. Use a comma between a subordinate clause and an independent clause in a sentence when the suborninate clause comes first:
Because she tried to swallow a bee, Kitty woke up this morning with hives covering her body.

(Oh, and for the record, whoever told you never to begin a sentence with the word "because" was, of course, dead wrong as you can see from the sentence above. Just be sure that when you do, the subordinate clause is followed by an independent clause, so you don't have a fragment.)

5. Use a comma following a conjunctive adverb (therefore, consequently, however, thus, moveover, also, finally, anyway, etc.) that introduces a sentence:
I got paid today. Therefore, I can't wait to go shopping.

Category #2 - Constructions that prohibit a comma
1. Do not use a comma before a subordinating conjunction (for, and, not, but, or, yet, so) if what follows the conjunction is not a complete sentence:
I got paid today and can't wait to go shopping. (Compare with Rule #2 in Category #1.)

2. Do not use commas to set apart essential elements in a sentence:
My friend who is wearing the red ribbon in her hair is named Juliet. (In this case, the clause "who is wearing the red ribbon in her hair" identifies which friend I'm referring to and is, therefore, essential to the sentence so not set apart with commas. Compare with Rule #3 in Category #1.)

Category #3 - Situations in which a comma is optional
1. Use commas to separate items in a list. The final comma before the conjunction is optional. (Note: I like it there. I think it eliminates all sorts of terrible confusion; however, it is optional.):
I have lived in Oregon, Washington, California, Montana, and Utah. (Comma after "Montana" is optional, but I recommend it.)

2. If a a sentence has an independent clause followed by a subordinate clause, a comma after the independent clause is optional. (Compare with Rule #4 in Category #1.):
Kitty woke up this morning with hives covering her body because she tried to swallow a bee. (Note, a comma after the word "body" is optional, but I don't like it there, so I left it out.)

Those are the most common issues with commas. Hope that helps, Rachael.

Enjoy your breathing, everyone. Just don't confuse it with comma usage.