The words you choose to write are not the whole manuscript. They need the right punctuation in order to convey your message clearly to your readers. One of the most common punctuation marks is the comma. Just because it is common does not mean that using the comma is easy. There are many functions and rules associated with the comma. Knowing the rules can help you not only use commas correctly but also to your advantage.
As far as punctuation goes, the comma is very versatile and fulfills many different functions. I could probably create an entire series on comma usage alone. The following uses are only a few of the ways commas help your writing. It’s a good idea to read about commas in your preferred style guide to learn all the different usages and their associated rules.
The first way you can use commas is in combination with a coordinating conjunction to separate two independent clauses. The comma precedes the conjunction, which is commonly and, but, or, etc. The conjunction separates the two clauses, but the comma adds an extra pause that assists the conjunction in creating a true separation. This usage occurs a lot, but it is not always so simple. Sometimes I’ll see a sentence that is technically one clause treated as if it is two because of a compound object or some other ending phrase. There needs to be at least a separate subject and verb on each side of the conjunction in order for it to qualify as two independent clauses that need a comma.
You can also use commas to create lists of words, phrases, and clauses. The one sticking point about using commas in a list is the Oxford comma or the comma that precedes the conjunction in the list. Some writing styles use it while others omit it. It is, in fact, a contentious point amongst grammarians, editors, and writers. As you can see from my lists in this paragraph, I use the Oxford comma. Occasionally, there does come a time when it creates more confusion than it solves, but I feel like that happens less often than when the comma is omitted.
Similar to its function in separating independent clauses, commas can also separate phrases and dependent clauses from the rest of the sentence, much like the phrases in this sentence. This comma function can be tricky because you must balance clarity with meaning. The pause from the comma (or lack thereof) will affect your meaning, but the comma’s placement will also affect how well your readers will understand the sentence. Dangling modifiers and other misplaced phrases happen partially because of poor wording but also because of comma placement.
A final usage for commas is signaling when something is nonessential information. Some parts of this usage really aren’t as necessary anymore as others. In the case of nonessential phrases and clauses, commas are still used regularly to separate them from the sentence. It is normally easy to identify nonessential information because the sentence will still make sense without that clause or phrase.
When it comes to nonessential words, usage is much more spotty. I don’t think many authors are worried anymore about following this part of the usage because the average reader doesn’t recognize the difference. For instance, let’s say someone is talking about their brother. If they say, “My brother David is coming for dinner,” the absence of any commas suggests that the brother’s name is essential, either because he’s not the only brother or because it is important information to the speaker. However, if the same person says, “My brother, David, is coming for dinner,” the commas now make the name nonessential, meaning it doesn’t add value to the main sentence. It’s merely been tacked on as something extra. I don’t think many authors are worried anymore about following this part of the usage because the average reader doesn’t recognize the difference. It is really a matter of how grammatically correct you want to be.
Knowing how to use commas is one thing, but it is entirely another to use these rules to your benefit. The comma can be a powerful tool, and you don’t want to waste it in your writing. You can use a comma to create different meanings or tones based on where you place it in a sentence. It is also useful for clarity and making sure your readers will understand points that might be vague or possibly confusing. Commas are essentially your way of signaling to readers so that they read your words in the way you intended.
The comma might seem like a small and unimportant punctuation mark, but it can be a powerful friend to a writer. You can use these three comma functions, and plenty of other ones, to improve the meaning and clarity of your writing.