May 26, 2017
The interrogative pronoun “who” seems to give users quite a bit of trouble; it is one more error in spoken English that tends to creep into the written form. Like a noun, it has to be declined in a sentence. “Declined” means its inflection (ending) has to vary according to its case or function in a sentence. Its cases are:
Nominative case — who
Accusative (object of a verb) — whom
Genitive (possessive case) — whose
Dative and Ablative cases — whom. “SEND NOT TO ASK FOR WHOM THE BELL TOLLS, IT TOLLS FOR THEE.”
Note: the genitive form is whose, not who’s (which may seem contra-intuitive!)
Example:
It is wrong to ask, “Who are you talking about?” The key here is the preposition “about,” which, like the other prepositions (on, for, with, upon, about), introduces the ablative case.
So we say: about whom (not about who); for whom (and not for who).
Question:
Which of the following two sentences is correct?
- He is the one whom I told you about.
- He is the one who I told you came home.
Answer:
They are both correct. In (1) “about” again clues us to the ablative case. In (2) “who” is in the nominative (not ablative) because it is the subject of the phrase “who came home.”
Perhaps a clarification with two commas would help make this clear: He is the one who, I told you, came home.

