I just read a mystery by Sue Grafton in which her character Kinsey Millhone mentally corrects a maid who responds to her phone call by asking “Who may I say is calling?”
The Millhone character thinks “Whom, sweetheart, Whom shall I say is calling…”
This passage illustrates the fact that even an excellent writer can have trouble with when to use who and when to use whom.
In this case, the maid was right and the detective was wrong. If you want to know why, read on.
Like most pronouns, who has two forms: a subject form, who, and an object form, whom.
To understand the use of pronoun pairs such as who/whom, he/him, she/her, I/me, they/them, and we/us when used with a verb, one must recognize whether the word is being used as the subject of the verb or as its object.
Every verb has a subject. The subject is the doer of an action:
We shop in town.
Who knows the secret?
Some verbs have objects. The object receives the action:
The ball hit me.
Don’t forget us.
Whom do you like best?
Most of the time we have little trouble recognizing subject and verb because the subject usually comes before the verb and the object comes after it.
The difficulty with who/whom arises from the fact that in a question, word order is reversed. We say “Where are you going?” and not “You are going where?”, “Whom do you like best?” and not “You do like whom best?”
Things get really sticky when a sentence contains more than one clause (i.e., more than one set of subject and verb).
The maid’s response is made up of two clauses. That is, it has two verbs: shall say and is calling. The subject of shall say is I. The subject of is calling is who. The clauses can be constructed in various ways:
Who is calling, shall I say?
Shall I say who is calling?
Who shall I say is calling?
The irony of Grafton’s criticism of the maid’s use of who is that elsewhere in the novel, Millhone doesn’t always use whom when it would be appropriate.
The use of whom as the object form of who is on its way out of the language. More and more educated speakers and writers use who as both subject and object. There doesn’t seem to be any reason not to. “Who do you want?” has become acceptable. Indeed, to the American ear, “Whom do you want?” sounds excessively proper. Personally, I like to observe the difference between who and whom in my writing, but I rarely do in speaking.
Whatever you do, don’t use whom as a subject! I’ve seen it done, further proof that this particular point of grammar has lost its significance. If you aren’t sure whether to use who or whom, go with who.