Common Punctuation Mistakes

With so many rules and different style guides, it’s hard to know what punctuation to use where in your writing. From comma splices to overuse of ellipses, there are a lot of mistakes you can make that cause you to look less than your best. I know—we all make mistakes. The mistakes I’m going to list below are based on The Chicago Manual of Style, as that is the most commonly cited style guide for writing, editing, and publishing fiction. There are different rules based on the various guides, so be wary of what type of writing you’re working on.

1. Comma Splices
   Comma splices happen when two independent clauses are joined by a comma. For example:

John ate dinner with us last night, we had a good time.

You could write this idea differently in a couple different ways.

John ate dinner with us last night. We had a good time.
OR
John ate dinner with us last night; we had a good time.

2. Incorrect Use of Hyphens, En Dashes, and Em Dashes
Yes, there is a difference between the three.

Hyphens are used to join two or more words together, such as when two or more words are connected and are modifying another word (to avoid confusion). A good example is up-to-date. Another good example, as given in the CMS, is to compare small animal hospital with small-animal hospital. The first indicates a regular animal hospital that is small in size. The second means a hospital that is only for small animals. It’s important to note that Chicago drops the hyphen when the modifying phrase comes after the noun. For example:

That well-known book is big right now.
OR
That book is well known and big right now.

The hyphen can also be used as separators, such as when you have a character spelling out something:

“My name is Skylar. That’s s-k-y-l-a-r.”

En Dashes typically connect (or deal with) numbers. (Words? Not nearly as often.) It means up to and including (or through) with continuing numbers. It can also indicate an unfinished range of numbers. Note that there should be no spaces around the dash. (Not in Chicago Style, anyway.)

John lived 1920–2005.
Barry Wolfe (1965–) or Barry Wolfe (b. 1965)

According to the CMS, the en dash can sometimes replace a hyphen in the use of compound words, as long as it makes sense or there isn’t already a hyphen in one of the words.

Em Dashes are probably the most well known of all the dashes. They separate an explanatory element in a sentence—instead of commas, parentheses, or colons.

I bought three antique books—all Nancy Drew Mystery Stories that are first or early editions—at the bookshop down the road.

You can also use em dashes around dialogue to indicate sudden breaks. If the break belongs outside the dialogue, then the em dashes go outside the quotation marks. For example:

“I didn’t know, and”—her voice grew hoarse with desperation—”there was no way I could’ve known.”

Bear in mind that you should never use a comma, colon, or semicolon directly in front of an em dash. A question mark or an exclamation point, however, can be used in such a manner. You can also use em dashes in place of commas for a more stylistic type of writing:

“How could you—” began Catalina, but Rob cut her off.

3. Overuse of Commas
This mistake seems to be a commonly cited one, but it’s one I personally tend to make when writing first drafts. I apparently have an affinity for commas, which means I have to carefully edit my writing during revisions for excess punctuation. To give an example:

The girl, however, started to get dressed, pulling on jeans and a t-shirt, but, her boyfriend ignored her, all while lying in bed.

The above is a huge mess of a sentence that needs to be broken up. While it’s (technically) grammatically correct, it makes for quite awkward reading with so many pauses. You could fix it up several different ways, but one definite edit is to split this up into more than one sentence:

The girl started to get dressed, pulling on jeans and a t-shirt. Her boyfriend ignored her, all while lying in bed.

4. Not Using Enough Punctuation
Similar to comma splices, I mean run-on sentences. Independent clauses that aren’t joined by a conjunction need to be separated by proper punctuation, whether that’s a semicolon or a period. Don’t use a comma to separate two independent clauses unless a conjunction divides them. By this, I mean the two independent clauses should have separate subjects and verbs, and the clauses should be separated by a word such as and, but, if.

One of my Nancy Drew books is first edition it’s dated 1948 and the dust jacket is still on!

This example definitely needs to be split up, such as:

One of my Nancy Drew books is first edition; it’s dated 1948, and the dust jacket is still on!

5. Not Using the Oxford Comma
The Chicago Manual of Style adheres to the use of the Oxford comma. It’s the last comma in a series that comes before a conjunction. For example:

Oxford comma: I studied Spanish, Latin, and French.
Without Oxford comma: I studied Spanish, Latin and French.

There’s a ton of debate over this one little comma, depending on which style guide you’re following. Following the CMS? Use the Oxford comma.

The beautiful—and frustrating—thing about English is that there are so many variations of the rules. Writing is such a subjective and stylistic art, meaning we all write in our own way. What punctuation faux pas have you made in your own writing? (We all make mistakes.) I’d love to hear from you in the comments!