A Tricky Thing About Commas: Appositives
Here’s something I see a lot of in my copy editing work: He’ll interview author Rob Peters and an accountant Jane Farrell.
Or sometimes it will look like this: He’ll interview author, Rob Peters, and an accountant, Jane Farrell.
But almost never will it look like this: He’ll interview author Rob Peters and an accountant, Jane Farrell.
As you may have guessed, that’s unfortunate because the last one is actually correct.
Knowing when to use commas in these situations lies in understanding appositives. And the easiest way to think of an appositive is as a renaming of something just said:
… my husband, Ted …
… the teacher, a great person ...
... your car, a 2009 Acura …
An appositive is a noun phrase that stands in apposition to another, where “apposition” means “a grammatical construction in which two usually adjacent nouns having the same referent stand in the same syntactical relation to the rest of a sentence.” (You can see why I led with the CliffsNotes version.)
Simply put, if you’re just throwing in a name or another noun that repeats another noun, that's an appositive. An aside. An extra parenthetical bit thrown in. And once we undertsand that, the “Chicago Manual of Style’s” advice is clear:
“A word, abbreviation, phrase, or clause that is in apposition to a noun is set off by commas if it is nonrestrictive -- that is, omittable, containing supplementary rather than essential information. If it is restrictive -- essential to the noun it belongs to -- no comma should appear.
“The committee chair, Gloria Ruffolo, called for a resolution.
“Stanley Groat, president of the cporporation, spoke first. …
“My older sister, Betty, taught me the alphabet.
“My sister Enid lets me hold her doll. (I have two sisters.)”
See how in the first sister example the lack of commas tells us that the speaker only has one older sister? And see how in the second sister example the lack of commas tells us that Enid is just one of two or more sisters?
Now think about “the baker Rob Peters” vs. “the baker, Rob Peters.”In the first, you’re using the name to make clear which baker you’re talking about. In the second, you’re implying that the reader already knows that you’re talking about one specific baker and that, by the way, his name is Rob Peters.
Ditto that for:
“I read the book, ‘Blue Skies” vs. “I read the book “Blue Skies.’”
In the first one, it’s clear you’ve already established with the reader that you’re talking about a single, specific book, even if you haven’t named it yet: “I went to the store. I thumbed through a book I couldn’t put down. I bought it, along with a music CD. When I read the book, “Blue Skies,” it changed my life.”
But in the second one, you’re probably referencing the book for the first time.
Again, it all boils down to whether the second noun phrase is a mere repeat of the first or whether they’re working together in a way that makes them inseparable.