There are two words in English that you have heard and most likely used, but one of them may be challenging to use correctly: that would be the word "whom."
Let’s take a look at both “who” and “whom” in more detail, and hopefully it will all make sense.
When to use “who”
The word “who” is used as the subject of a sentence, which means it’s a noun, the person the sentence is about, or the person who is doing the action. It is used as a pronoun. This is the easy word to use correctly in American English.
Who is that?
Who are you?
Who hit my car?
When to use “whom”
The word “whom” is never the subject, it is always what we refer to as the “object of the sentence.” This is the word that most people are not sure how to use or when to use it.
You are going with whom?
Mark recommended whom for the new position?
There are two tricks you can use to tell when to use “whom” that should help make it easier to use correctly.
1. When “whom” is the object of the sentence, you should be able to replace it with “him” or “her”, and the sentence will still be grammatically correct.
You recommended whom for the position?
We can also say: You recommended him for the position?
You recommended her for the position?
The words “whom”, “him” and “her” are all objects of the verb “recommended.”
2. The word “whom” is often used before a preposition. When this happens, we say that “whom” is the object of the preposition. Common prepositions that come just before “whom” may be “with”, “after”, “before”, “over”, “next to”, “under”, etc.
For example: With whom are you driving?
You are in line after whom?
I don’t know from whom that package came.
Now that you know when to use “who” and “whom” correctly, it may sound somewhat weird or awkward to use “whom”, even when it is technically correct. Why is this? American English is changing, and even though grammar rules for these two words still apply, the word “whom” is gradually being used less and less. It may even eventually disappear from the language altogether. When in doubt, use “whom” in a very formal speaking situation, especially is others around you are using it.
As I always say, you cannot go wrong following grammar rules! It just may depend on “with whom” you socialize or “who” is with you!