"Who" and "whom" are NOT interchangeable!!

Ok, this is just a little diatribe on the use of "who" and "whom". I don't really mind when people just use "who" for everything. In fact, since English grammar relies partly on sentence structure to convey meaning, it doesn't really affect an audience's ability to understand. However, I can't stand when authors and speakers throw "whom" around incorrectly in a vain attempt to sound intelligent. I had someone doing just that earlier today, so I decided to explain when to use it.

To truly understand when to use "who" vs. "whom," you need to understand relative phrases. Relative phrases are really a type of subordinated sentence, whose subject noun phrase is converted to a relative pronoun. They're then used to modify the same noun phrase in a different sentence.

Here's a simple example. We start with two sentences. "The author wrote the book," and, "The author gave a speech." Notice that they share a noun phrase: "The author". We want to turn the first sentence into a relative phrase that modifies the noun phrase in the second. To do this, we replace the noun phrase with a relative pronoun, in this case "who", and move the relative pronoun to the front of the sentence if it's not already there (the relative pronoun is the signal that a relative phrase follows, so it must be first). So, the first sentence becomes "who wrote the book," and our combined sentence reads, "The author who wrote the book gave a speech."

Got it? Once you understand how relative phrases are created, figuring out whether to use "who" or "whom" becomes simple. Use "who" if the noun phrase you're replacing is the subject of the sentence and "whom" if it's the object. Let's modify our example slightly to illustrate. Let's make our first sentence, "The audience adored the author," and leave our second, "The author gave a speech." Now, when we change the first sentence into a relative phrase by replacing the noun phrase with a relative pronoun and moving it to the front of the sentence, it becomes, "Whom the audience adored," and our combined sentence becomes, "The author whom the audience adored gave a speech."

Make sense? That's all there is to it! Now, if only everyone would read this...

(Side note: The discussion on how relative phrases are created will resume when I discuss why I believe it's perfectly OK to end sentences with prepositions. Such suspense, I know!)