"Hey, Joe, where are you going with that gum in your hair?"
In that sentence, you're addressing Joe directly (while also magically transforming a bummer of a 1960s rock anthem into an art form).
"You, sir, have the boorish manners of a Yalie."
That sentence, which I pilfered from "Gilligan's Island" and which I used to utter frequently to my cat, Stevie, also makes a direct address. Notice that I'm not calling Stevie by name. "Sir," "ma'am," "professor," "buddy," "hot shot" — anything you use in place of a name is also a direct address.
The "Associated Press Stylebook" and the "Chicago Manual of Style" agree that direct addresses require commas. A lot of screenwriters don't seem to know this. In an otherwise flawless screenplay, you might see in the dialogue: "Go ahead Milton. Make my day." But you need a comma before that "Milton."
Which brings us to another point about commas: They often work in pairs. When a comma is used to set off what we call parenthetical information — extra stuff inserted but not needed — you usually need two of them.
"Listen, Milton, this accounting office isn't big enough for the two of us."
Here, "Milton" needs not just that first comma, but that second one as well. People who find this simple and self-evident are often baffled when it comes to applying it to dates and to "Inc." But these cases are just as simple.
"Snoozer Films, Inc., also owns the Gummy Head Joe record label."
Log on to just about any press-release wire service and for every release that gets it right — that is, uses two commas — there are probably eight that get it wrong, using only one comma. Even Microsoft Word's grammar checker doesn't get it. But if you were to read aloud with a nice long pause for the comma, "Snoozer Films, Inc. filed for bankruptcy," you'd take a long breath after "Films" and read "Inc." with a fresh lungful of air, as if it were a new sentence. And that would be just silly.
So if you use a comma before "Inc." you need one after it, too.
Ditto for the years in dates. "March 17, 2007, is the date that June will be celebrating her 29th birthday again."
When people leave out that second comma, which many do, I call it the "jilted comma" — a poor little punctuation mark without its mate.
I'll squeeze in one more note about commas. You know how, when you were a kid, they taught you to use a comma before words like "too," "also," "either" and "anyway"?
Well for some reason no one can seem to explain, those commas are falling out of vogue. If you look you'll notice more and more books and magazines writing omitting this comma.
I don't know why. I don't make the rules. I just interpret them through my art.
JUNE CASAGRANDE is author of "Grammar Snobs Are Great Big Meanies." She can be reached at word@ grammarsnobs.com.