Last night I flew home from teaching in South Carolina, and this morning I had an email from one of my new Carolina friends:
"I just thought of a question about something we didn’t cover: when to use who vs. whom. . . . Any quick tips?"
The quick tip is this: Who is used as a subject; whom is used as an object.
Explanation: Who is used in the same situations as I, he, we, they, and other subject pronouns. Whom is used where me, her, him, us, and other object pronouns fit.
Who wrote the letter? (I, he, we wrote the letter.)
Whom shall I ask? (I shall ask him, her, them.)
The tricky part is that whom is often avoided, even by careful speakers and writers. That’s because it seems more natural to say "Who shall I ask?" and "Who will you vote for?" In both of these sentences whom is correct, but who is more commonly used.
Once you know the rule, you can decide whether a situation requires perfect grammar or natural-sounding speech. Then choose accordingly.
Different language for different places? Sure! In South Carolina, I was special as "Miss Lynn." Back home in Seattle, I’m just plain old Lynn.