Special Uses of the Comma
The comma is one of the most frequently used—and frequently misused—pieces of punctuation. Commas are most commonly used to combine two phrases and clauses into one sentence, or to help separate items in a series, but that’s not the only time they are used.
Commas are versatile and are used for a ton of miscellaneous purposes in English. It’s more convenient to have one punctuation mark do many different things than having a bunch of unique punctuation for every purpose, but it does mean that sometimes it can tough keeping everything straight. Here are some of the special uses of commas to keep an eye out for.
An absolute phrase modifies the whole sentence—it’s basically a phrase that works like an adjective but for the entire rest of the sentence. A comma is used to separate it from the rest of the sentence, like so:
His arms folded across his chest, the professor sternly told us how to use commas.
In American English, commas are used to separate the day from a year—July 4, 2016. Careful, however—when you say the day before the year, as in British English, you do not use a comma—4 July 2016.
In American English, commas are used to divide numbers into thousands, so we’d say 2,100 or 8,675,309. In British English, they use periods instead to separate the thousand blocks, so pay attention to what format you’re using when adding commas. Generally, you do not add commas in years, addresses or page numbers, even when they are in the thousands.
If the person you’re writing about has a special title or degree, then you use commas to separate that out from the rest of the sentence. For example: Kevin Knowles, Ph.D., will be giving the talk.
While you don’t use commas in four- or five-digit addresses, you do use it to separate parts of an address. For example, I’m writing this blog post in Oak Park, Illinois, in my apartment. You do not use a comma, however, before a ZIP code.
A conversational tag is a phrase like “You know,” or “well,”—it’s not actually adding meaning to the sentence, but they pepper our everyday speech. You separate this from the rest of the sentence with a comma like so:
You know, I’m not a big fan of the new Independence Day movie.
If you’re directly addressing someone in your writing, saying their name, then you can separate that out from the rest of the sentence with commas as well, like so:
Your plan to build a rocket to the moon, Mr. Kennedy, has a few significant problems.
If you ever have any comma-related questions, stop by Wordsmith Essays’ order page, where our team of international editors can help make sure every punctuation point is in precisely the proper place.