A Word, Please:

I remember when I first learned how to form the possessive of a compound like “John and Sue.” Reading my “AP Stylebook” one day, I discovered exactly when to use “John and Sue’s beliefs” and when it should be “John’s and Sue’s beliefs.”

I was so proud, floating around on the high of discovery for months. Years later, I’m still rather pleased with myself for knowing this. Or I was, until last week when someone asked me: Is it “John’s and my beliefs” or “John and my beliefs”?

So much for my pride.

You see, reference books like the “AP Stylebook” and the “Chicago Manual of Style” give very specific directions for what to do when two nouns like “John” and “Sue” possess something. But they don’t give a lick of advice on what to do when one of the possessors is not a noun but a word like “my,” which is called a possessive determiner and really works like an adjective.

Here’s how the style guides say to make possessives out of two nouns.

The choice between “John’s and Sue’s” and “John and Sue’s” depends on whether they share the possessed thing. If John and Sue share, say, a house, they share an apostrophe and S, too. “We visited John and Sue’s house.”

But if you’re talking about things they own separately, then each gets an apostrophe and S. “We visited John’s and Sue’s houses.” In fact, this is how to tell your reader that John and Sue have separate houses. Had you said, “We visited John and Sue’s houses,” you’d know that John and Sue together own more than one house.

It’s easy — until you swap out one of the nouns for a possessor that begins with a modifier like “my.” If John and I owned separate houses, you’d get “John’s and my houses.” But if those houses were in both our names and you applied the standard rule, you’d get “John and my houses.”

That sure doesn’t sound right.

So, when someone asked me about this, I rolled up my sleeves, plunked a stack of books down on my desk and started digging. Neither AP nor Chicago addresses the issue. Nor does “Garner’s Modern American Usage” or several other books I turn to for advice in sticky grammar situations.

It’s a curious omission. “John’s and my” seems to vex a lot more people than “John’s and Sue’s.” I can’t count the times I’ve heard people stumble over, “We’ll be celebrating John’s and my anniversary this month.”

That applies to all the other possessive determiners, too — his, her, your, our, their and its. Did you take Katie’s and her advice? Or Katie and her? Did you enjoy Mr. Thompson’s and your conversation? Or Mr. Thompson and your conversation? Just the thought of having to say something like this seems to make most people’s voices drop down to insecure murmurs.

Determined to find an answer, I e-mailed a friend. Her name is Mignon Fogarty, but you may know her as Grammar Girl. Did she, I asked, have a source on this matter?

Turns out she did. She pointed me to page 170 in her delightful book “The Grammar Devotional,” where she argues that the rule you use when two nouns share possession of something doesn’t apply in “my” situations because “my” isn’t a noun. Thus, you attach the apostrophe and S to the noun — to the “John” in “John’s and my” whether the possession is shared or not.

So it’s: John’s and my house. Lynne’s and his car. The president’s and her daughters. And, of course: June’s and your newfound pride in knowing how to deal with yet another grammar conundrum.

Get in touch JUNE CASAGRANDE is a freelance writer and author of “Grammar Snobs Are Great Big Meanies” and “Mortal Syntax: 101 Language Choices That Will Get You Clobbered by the Grammar Snobs — Even If You’re Right.” She may be reached at JuneTCN@aol.com. Get in touch JUNE CASAGRANDE is a freelance writer and author of “Grammar Snobs Are Great Big Meanies” and “Mortal Syntax: 101 Language Choices That Will Get You Clobbered by the Grammar Snobs — Even If You’re Right.” She may be reached at JuneTCN@aol.com.