Why Commas Matter

Learn how a single comma can change the meaning of your sentence.

Mignon Fogarty
1-minute read

Why Commas Matter

While writing Dashes, Parentheses, and Commas I missed an opportunity to explain the difference between a restrictive element and a nonrestrictive element. Silly me! The following sentences mean different things:

    The monks, who were running, jumped aside. (nonrestrictive)

    The monks who were running jumped aside. (restrictive)

It's all about the commas.

When “who were running” is in commas, it's a nonrestrictive element — an aside. It's describing the monks, which means every monk was running. You can leave it out and it doesn't change the core meaning of the sentence.

When “who were running” isn't in commas, it's a restrictive element — it modifies the noun “monks.” Only some of the monks were running, and it was those running monks who jumped aside. Leaving it out would leave out important information about what happened.

About the Author

Mignon Fogarty

Mignon Fogarty is the founder of Quick and Dirty Tips and the author of seven books on language, including the New York Times bestseller "Grammar Girl's Quick and Dirty Tips for Better Writing." She is an inductee in the Podcasting Hall of Fame, and the show is a five-time winner of Best Education Podcast in the Podcast Awards. She has appeared as a guest expert on the Oprah Winfrey Show and the Today Show. Her popular LinkedIn Learning courses help people write better to communicate better.