Many years ago, back when I used to answer my land-line telephone, I found myself in a conundrum. I realized that, when a caller asked, “May I speak to June, please?” I would answer “This is she.” But I couldn’t for the life of me explain why. Why did I use the subject form, “she,” for a pronoun in a spot that seemed to call for the object form, “her”? I had no idea.
I tried “This is her” on for size. It sounded funny. Worse than funny. Wrong. I went back to saying, “This is she,” but I didn’t feel good about it. I felt like I was using fancy, formal grammar I didn’t even understand. I felt like a fraud.
I asked around, quizzing co-workers at the newspaper where I then worked if anyone could explain why it’s standard to say “This is she” instead of “This is her.” None of the writers or editors could. But an administrative assistant, one of those stunningly competent workers who hold whole entire companies together but never get proper credit or compensation, threw a term at me: predicate nominative.