One of the viewers of this video series wrote to me and asked, “Could you just explain how to use ‘who’ and ‘whom’?”

I’m happy to do so, but I have to warn you that adhering to the traditional rule about using “who” and “whom” may make you sound funny to yourself and other people. The word “whom” has been in decline for quite a while, and it can now sound old-fashioned in many contexts, if not pretentious.

Here’s the rule: “Who” should be used as a subject form. “Whom” should be used as an object form (i.e., the object of a verb or preposition).

All nouns in English used to make a distinction between subjects and objects, but that system of grammatical case has been lost in the history of English. Now it’s only pronouns that distinguish between subjects and objects—and not even all pronouns do it. For example, consider the pronoun “you”: The form “you” serves as the subject and as the object. But the pronouns “I” and “me,” “she” and “her,” “he” and “him,” “we” and “us,” “they” and “them,” as well as “who” and “whom,” still make a distinction.

“Who” can be both an interrogative pronoun (e.g., “Who gave you the book?”) and a relative pronoun (e.g., “the person who gave me the book”). I’ll focus on the interrogative, but the same pattern holds for the relative pronoun. I think at this point some examples may help explain the rule.

Let’s start with “who” as a subject. It would be used in a question like this: “Who saw you run the red light?” In this case, “who” is the subject of the clause. The interrogative pronoun becomes the object in questions like these: “Whom did you see?” and “Whom did you send it to?” Because the pronoun functions as an object in both questions, I have used “whom.”

But would you really ask the questions that way? I would tend to say, “Who did you see?” or “Who did you send it to?” If I ask, “Whom should I send it to?” (or “To whom should I send it?”) I sound a little too much like an English professor, which I am, but I don’t try to sound that way all the time.

We have evidence people have been using “who” for “whom” for centuries.

Confusion about these two words goes back (at least) to the 15th century. Some of the confusion probably stems from the fact that the interrogative pronoun is regularly moved to the front of the sentence, even when it serves as an object. That is, we typically would ask “Who/whom did you see?” rather than “You saw who/whom?” Up there at the front of the sentence, the pronoun can look like a subject even when it is functioning grammatically as an object. From this perspective, it can seem remarkable that “whom” is still in the language and has not just given way to the word “who” so that the pronoun has only one form (the same way the distinction between “ye” and “you” collapsed a few hundred years ago).

If you were to ask me to put money on it, I wouldn’t bet on “whom.” I think its days may be limited. That said, I hope you now understand the rule and can make an informed decision about which word you want to use depending on who, or whom, you’re addressing.

This video originally appeared in LSA Today, where you can find more videos, including an archive of Anne Curzan’s discussions of language.