A Word, Please: Arguing grammar smartly

My husband has a smart phone. We go out to dinner, hear a song playing in the restaurant and within three minutes know the name of the song, the artist, the movies it was featured in, and which drug the singer overdosed on.

Then, when we get home, we use his phone as a flashlight to illuminate the keyhole in our door. It’s an amazing device.

Me, I have a dumb phone. It rings. I answer. I talk for a minute or two. Then I hang up. Advertisers would have me feeling like a chump for my inferior technology. But I feel like anything but a chump when I pay my bill, which every month comes to about $35 less than the data plans needed for those so-called smart phones.

In fact, the last time a phone made me feel dumb was when I realized I had no idea why people answer “This is he” instead of “This is him” or “This is she” instead of “This is her.”

I knew that people often opt for the subject pronoun (he or she) when they wanted to sound more formal, and that they may stick with the object form (him or her) when they are being more casual. But I couldn’t figure out the grammar of it.

It seemed to me that the object form was correct. After all, that’s the form used in so many similar sentences. I called her. I watched him. I knew them. The old subject-plus-verb structure just begs to be followed by an object. So “This is she” made no sense to me.

It took some digging, but eventually I found out that the answer has to do with something called the predicate nominative. And don’t let the name put you off. It’s actually a pretty simple concept.

Any time you have a noun or pronoun followed by a form of “be,” the thing that follows is called the predicate nominative. The predicate nominative literally renames the predicate (the first noun or pronoun). Look at the sentence “The butler was the murderer.” Here, the predicate is “the butler,” the verb is a past-tense form of “be,” and the noun that follows refers back to butler. In this case, “the murderer” is the predicate nominative. It’s the subject renamed.

Of course, a sentence like this isn’t confusing because “the murderer” doesn’t change form according to whether it’s a subject or an object. The murderer watched TV. The cops caught the murderer. It’s the same in either case.

But pronouns do change form according to whether they’re subjects or objects. He watched TV. The cops caught him. The subject pronouns she, he, I, we and they all have corresponding object forms: her, him, me, us and them. Grammarians call the subject form the “nominative case,” and they call the object form the “objective case.”

For predicate nominatives, there’s a simple principle we can apply: “If a pronoun is serving as a predicate nominative, it must be, of course, a nominative case pronoun,” writes Thomas Elliot Berry in “The Most Common Mistakes in English Usage.”

That’s why it’s grammatically correct to say to a caller “This is she” instead of “This is her.” It’s also why people speaking formally sometimes say “It is I” or “It is he” in place of “It is me” or “It is him.”

Obviously, you’ll never hear a character in a courtroom drama say, “That is he, your honor! That’s the man who did it!” In casual usage we often choose an object pronoun. It’s idiomatic, and there’s nothing wrong with it.

But if you know about predicate nominatives, you never have to wonder whether it’s wrong to say “This is she.”

JUNE CASAGRANDE is the author of “It Was the Best of Sentences, It Was the Worst of Sentences.” She can be reached at JuneTCN@aol.com.