Making Sense of Relative Pronouns “Who,” “Which,” and “That”

Quick Summary

Relative Pronouns

A relative pronoun is a word that connects a clause to a noun or pronoun and adds more detail about it. Some of the commonly used relative pronouns are “who,“ “which,“ and “that.“ Before we look at its grammatical role in detail, let’s start with an example:

He is my teacher who cares for every student.

In this sentence, the relative pronoun “who” refers to the noun “my teacher.” The clause that follows, “who cares for every student,” tells us more about what kind of teacher he or she is. From this, we understand that the teacher pays close attention to each individual student.

As you can see, a relative pronoun attaches extra information to the noun or pronoun that comes before it.

Rule of Using Relative Pronouns

When using relative pronouns, there are three key rules to keep in mind:

We’ll begin with the first rule.

Independent Clause Comes After a Relative Pronoun

Although there are several ways to use relative pronouns, they must always be followed by a clause, called a relative clause. Since the relative pronoun already refers to the noun before it, the subject of the relative clause is often not repeated.

You can think of the relative pronoun as a word that replaces the noun it refers to.

I have a friend who eats paper.

Here, the relative pronoun “who” refers directly to the noun “a friend.” It tells us more about that friend that this person eats paper. Because “who” already stands in for “a friend,” we don’t repeat the noun as the subject of the relative clause.

Therefore, the following sentence is both ungrammatical and unnatural:

* I have a friend who a friend eats paper.

Even though “a friend eats paper” is an independent clause by itself, repeating the subject makes the sentence incorrect and awkward.

However, it doesn’t mean that you can always omit the subject of the relative clause. Whether to remove the subject depends on the use of relative pronoun: the preceding part serves as subject or object of the relative clause.

Subjective and Objective Cases

Depending on whether the noun before the relative pronoun acts as the subject or the object of the relative clause, the structure that follows will change. Grammatically, this distinction is known as the subjective and objective cases of relative pronouns.

• Subjective case: the noun before the relative pronoun functions as the subject of the following relative clause.
• Objective case: the noun before the relative pronoun functions as the object of the following relative clause.

Here are the distinction between these two cases.

Here are examples of a relative pronoun used in the subjective case:

She is my sister who won the speech competition.

In this sentence, the relative pronoun “who” refers to “my sister.” It serves as the subject of the relative clause “who won the speech competition.” Because “who” already stands in for the subject “my sister,” the noun itself is omitted. This makes the sentence natural and grammatically correct.

My dog which barks a lot is usually quite.

In the sentence above, the relative pronoun “which” acts as the subject of the relative clause “which barks a lot.” Because it already serves as the subject, the noun “my dog” is not repeated inside the clause. Also, since the noun “my dog” refers to a non-human subject, the appropriate relative pronoun is “which,” not “who.”

Let’s look at some examples:

She is my sister whom a tall man is talking to.

In this sentence, you can see that “my sister” functions as the object of the relative clause. If we rewrite the relative clause as an independent sentence, it becomes

A tall man is talking to my sister.

Here, “my sister” is clearly the object of the clause. That’s why the original sentence uses the objective case, and the correct relative pronoun is “whom,” not “who.”

Here’s another example.

The cuisine which I had in India was unforgettably delicious.

In this sentence, the relative pronoun “which” refers to “the cuisine” and functions as the object of the relative clause. We can rewrite the relative clause as an independent sentence:

I had the cuisine (in India).

Here, the subject is “I,” the verb is “had,” and the object is “the cuisine.” The phrase “in India” simply provides additional information and does not affect the grammatical structure. The key point here is that “the cuisine” serves as the object of the clause.

Relative Pronoun “That”

The relative pronoun “that” can be thought of as a kind of wild-card pronoun — it can replace both “who” and “which.” Although “that” is often used interchangeably with them, it is generally more formal and precise to use “who” for people and “which” for things.