- I know the man who called him.
- I know the man whose voice I hear.
- I know the man whom they called.
In these three sentences we have the pronoun who used in its three forms, subject, possessive and object form. We should be very careful not to confuse the subject and the object forms of the pronoun who.
- This is the book which tells the truth.
- This is the book whose author is in prison.
- This is the book which I wanted.
In these three sentences we have the pronoun which used in its three forms, subject form, possessive form and object form. In the first sentence the pronoun is the subject of the verb tells; in the second sentence, it is used in the possessive form with the noun author; in the third sentence, it is used as the object of the verb wanted.
236. What differs from the other relative pronouns in that its antecedent is never expressed, for it is implied in the word itself. What is always equivalent to that which, or the thing which. For example, the sentence, Do not tell what I have told you, is equivalent to saying, Do not tell that which I have told you, or the thing which I have told you.
237. Never use what in a sentence as a relative pronoun unless you can replace it and make good sense by using that which, or the thing which in place of what.
For example, do not say, I know that what he would say. This is incorrect. You should say, I know that which he would say, or I know what he would say, using what in place of that which. Here is a sentence that occurred in an English examination recently, which illustrates most aptly this point. A subject is that what something is said about. Here what is used incorrectly. A subject is that about which something is said, would have been the correct form.
Watch for this in your speech for it is a most common error and to the educated ear is harsh and marks the speaker as uneducated. All of these mistakes which we make so commonly will require a considerable amount of effort to overcome, but the result is worth the effort, for even those about us who will not take the pains or give the required time and effort to acquiring an education for themselves, will give greater heed to the speech of those who do speak correctly, and will readily acknowledge the leadership of those who have given the time and effort to self-development.
238. The antecedent of who is sometimes omitted and understood; for example, Who follows the cause must endure hardship, He, is understood and omitted. He who follows the cause must endure hardship.
239. The relative pronoun itself is often omitted. For example: