Let’s talk about commas.
A comma is a saw slicing a branch from a tree trunk. A comma is a border collie herding unruly sheep into groups or a braid weaving together frizzy curls. It’s a dam diverting the stream around the colony of prairie dogs until the water can return to its original trajectory. A comma is the sneeze interrupting an insignificant part of the movie.
I’ve used a lot of strange analogies when trying to root punctuation rules, specifically comma rules, into a student’s mind. Put simply, commas are about creating clarity in a sentence. They are tools to organize your words and phrases.
Unfortunately, many people include far too many commas, which creates the opposite effect, confusing your meaning rather than clarifying it. Despite a prevalent theory circulated by well-meaning English teachers, deciding where I put a comma should not be determined by my need for a breath or pause. That one’s breath governs comma placement is one of the most common misconceptions about this punctuation mark. As one of my grammar-savvy teachers once said, “Commas aren’t biological.”
Think of punctuation as a separating agent: it pushes pieces of your sentence apart. I wouldn’t want to put a comma between essential parts of my sentence, like my subject (“the man”) and verb (“contemplates).
Examples of Comma Misuse: The man, contemplates why the sea is salty. [Don’t do this.]
The man who ran a marathon earlier that day, contemplates why the sea is salty. [Also, don’t do this. If you separated out the whole phrase “who ran a marathon earlier that day” with commas on either side, that would be okay.]
While punctuation rules can vary within different style guides and—like nearly everything in English—there are exceptions, there are 4 main comma guidelines that can help solve your comma confusion. (By no means are these all of the comma rules in existence, but they do appear in writing the most often.)
Commas should be placed after introductory phrases and clauses.
Introductory material could be a small phrase (“in the morning”), a word (“however”), or even a dependent clause (“while we stroll along the cliffside”). (Some popular guides say you only need a comma if there are more than 5 words in the introductory phrase. I tend toward including a comma even if the introductory material is less than 5 words because it adds clarity.)
Example: At the window overlooking the ocean, the man contemplates why the sea is salty.
Commas should separate list elements.
Example: The tired, grumpy man contemplates why the sea is salty, why birds glide against the waves, and to where waves retreat.
I separate my two adjectives “tired” and “grumpy” because they are interchangeable adjectives, meaning I could swap the adjectives around and it wouldn’t impact the meaning: “the grumpy, tired man.” If they were not interchangeable (i.e., “the tired American man”), then I would not put a comma.
I also place commas in my list of object phrases describing what the man is contemplating. I chose to use the Oxford comma (the comma prior to the “and”) because of personal preference, but many style guides, like the Associated Press, nix that comma.
Commas should separate out nonessential elements.
Example: The man, a father of three, contemplates why the sea is salty.
It’s very important when adding commas to material in the middle of the sentence to fully surround the extra info or nonessential material. For instance, if I just put one comma (“man, a father of three contemplates”), then I create a big problem because my subject is separated from my verb.
Commas should precede coordinating conjunctions (words, like “and” or “but,” that join equivalent parts of a sentence) when separating two independent clauses.
(Simple independent clause test: Is it a complete thought?)
Example: The man contemplates why the sea is salty, and the sea contemplates why the man rests on his crooked elbows.
Common Comma Mistake: The man contemplates why the sea is salty, and why the sky isn’t. [Don’t do this.]
Contrary to common thought, I do not need a comma before “and” or “but” all of the time. In the previous sentence, I’d be chopping off half of what the man is contemplating, an essential part of my sentence.
Correct Example: The man contemplates why the sea is salty but never fully arrives at a conclusion.
All this being said, you will see commas used in many incorrect ways, even in highly polished articles by prominent writers. Sometimes, it’s a stylistic choice; sometimes, it’s a simple matter of not knowing any better. My hope is that now you know better and that this brief guide can help you use commas to create syntactical harmony and clarity.