Once you learn about comma splices, you notice them everywhere, and a listener named Jo has started noticing them. She wrote, “Comma splices are the rage on the internet these days. Can you write about them sometime?” Well, I have written about them, but it was four years ago, so it’s definitely time for a refresher.
How to Use Commas
Commas are always tricky because there are so many different ways you can use them, but one of the most common ways to use commas is to separate two main clauses that are connected by a coordinating conjunction. That just means that when you join two things that could be sentences on their own with a word such as and, but, or or, you need a comma before the conjunction. For example
Squiggly ran into the forest to hide, and Aardvark realized he’d have to fight the peeves alone.
Squiggly ran into the forest to hide is a complete sentence, and Aardvark realized he’d have to fight the peeves alone is also a complete sentence. To join them with a comma, you need the word and or some other coordinating conjunction. If you just put a comma between them without a conjunction, that's an error called a comma splice or a comma fault. Here’s an example:
Squiggly ran into the forest to hide, Aardvark realized he’d have to fight the peeves alone. (wrong)