Who (pronoun)

The English pronoun who is an interrogative pronoun and a relative pronoun, used primarily to refer to persons.
Unmarked, who is the pronoun's subjective form; its inflected forms are the objective whom and the possessive whose. The set has derived indefinite forms whoever, whomever, and whoseever, as well as a further, earlier such set whosoever, ''whomsoever, and whosesoever''.

Etymology

The interrogative and relative pronouns who derive from the Old English singular interrogative hwā, and whose paradigm is set out below:

	Person	Non-person
Nominative	hwā	hwæt
Genitive	hwæs
Dative	hwǣm / hwām
Accusative	hwone	hwæt
Instrumental		hwȳ

It was not until the end of the 17th century that who became the only pronoun that could ask about the identity of persons and what fully lost this ability.
"The first occurrences of wh-relatives date from the twelfth century. The wh- form does not become frequent, however, until the fourteenth century." Today, relative whose can still refer to non-persons.
The spelling 'who' does not correspond to the word's pronunciation ; it is the spelling that represents the expected outcome of hwā, while the pronunciation represents a divergent outcome – for details see Pronunciation of English ⟨wh⟩. The word is cognate with Latin quis and Greek ποιός.

Uses

As interrogative pronoun

"Who" and its derived forms can be used as interrogative pronouns, to form questions:

"Who did that?"
"Who did you meet this morning?"
"Who did you speak to?"
"Whoever could have done that?"
"Whose bike is that?"
"Whose do you like best?"

The same forms are used to make indirect questions:

"We don't know who did that."
"I wonder who she met this morning."

The corresponding form when referring to non-humans is what. Another similar interrogative is which – this can refer to either humans or non-humans, normally implying selection from a particular set, as either interrogative pronoun or interrogative determiner . What can also be used as a determiner, but who cannot.
Which, who, and what as interrogatives can be either singular or plural. Who and what often take a singular verb regardless of any supposed number. The question "Who wants some cake?" does not presuppose anything about number in possible responses, as does the question "What's in the bag?".

As relative pronoun

The other chief use of who and its derivatives are in the formation of relative clauses:

"These are the men who work upstairs."
"This is Tom, who I believe you have already met."
"I helped some lads whose car had broken down."

The corresponding form for non-humans is which, although whose can be used as a possessive in relative clauses even when referring to non-humans: "I will have to fix the car whose engine I ruined."
In restrictive relative clauses, when not preceded by a preposition, both who and which can be replaced by that. In relative clauses, who takes the number of its antecedent. Who also takes the person of its antecedent:

"I, who am having a hard time right now, won't be able to help you."
"I, a tired old man who is fed up with all your nonsense, refuse to help you."

Who and whom can also be used to form free relative clauses. The emphatic forms are often used for this purpose: "I'll take whoever you choose" or "I'll take whomever you choose". This corresponds to the use of what when referring to non-humans. and whom
The emphatic forms can also be used to make adverbial clauses, as in "Whoever you choose, I'll be satisfied".

Usage of "whom"

Tendency to replace ''whom'' with ''who''

According to traditional prescriptive grammar, who is the subjective form only, while whom is the corresponding objective form. It has long been common, particularly in informal English, for the uninflected form who to be used in both cases, thus replacing whom in the contexts where the latter was traditionally used.
In 1975, S. Potter noted in Changing English that nearly half a century prior, Edward Sapir predicted the demise of whom, showing at great length that it was doomed because it was "psychologically isolated" from both the objective pronouns and the invariables. By 1978, the who–''whom distinction was identified as having "slipped so badly that almost totally uninformative". According to the OED, whom is "no longer current in natural colloquial speech". Lasnik and Sobin argue that surviving occurrences of whom are not part of ordinary English grammar, but the result of extra-grammatical rules for producing prestige forms.
According to Mair, the decline of whom has been hastened by the fact that it is one of relatively few synthetic remnants in the principally analytical grammar of Modern English. It has also been claimed that the decline of whom is more advanced in the interrogative case than in the relative case, this possibly being related to the degree of complexity of the syntax.
Some prescriptivists continue to defend whom as the only correct form in functions other than the subject. Mair notes that whom is "moribund as an element of the core grammar of English, but is very much alive as a style marker whose correct use is acquired in the educational system . is highly restricted, but rather than disappear entirely, the form is likely to remain in use for some time to come because of its overt prestige in writing."
Whom is also sometimes used by way of hypercorrection, in places where it would not even be considered correct according to traditional rules, as in "Whom do you think you are?" For more examples see the section below.
Retention of the who–whom distinction often co-occurs with another stylistic marker of formal Englishavoidance of the stranded preposition. This means that whom can frequently be found following a preposition, in cases where the usual informal equivalent would use who and place the preposition later in the sentence. For example:
"To whom did you give it?"
"Who did you give it to?"
In relative clauses, movement of the preposition further allows whom to be replaced by that'' or removed entirely:

"He is someone to whom I owe a great deal."
"He is someone who I owe a great deal to.", "He is someone that I owe a great deal to.", or "He is someone I owe a great deal to."
Difference between ''who'' and ''whom''

In the types of English in which whom is used, the general grammatical rule is that who is the subjective form, while whom is the objective form. Thus, who is used as a verb subject, while whom is used as an indirect or direct object of a verb or as the object of a preposition.
Examples:

As verb subject: "Who is waiting over there? Tom is someone who works hard"
As verb object: "Whom do you support? She is someone whom many people admire."
As preposition complement: "On whom do you plan to rely? These are the players of whom I am most proud."

Notice that in a relative clause, the form depends on the role of the pronoun in the relative clause, not that of its antecedent in the main clause. For example, "I saw the man who ate the pie"not whom, since who is the subject of "ate" ; it makes no difference that its antecedent " man" is the object of "saw".
In the position of predicative expression, i.e. as the complement of forms of the copula be, the form who is used, and considered correct, rather than whom.

"Who were those people?"
"Who is this?"; "It is I." or "It is me.".

In the examples below, notice how, when the verb is a form of be, the question "Who is the captain of the team?" or the noun clause "who the captain of the team is" is the same regardless of whether the original placement of the unknown person was before or after be :

She asked something. John is captain of the team.
*Interrogative: She asked, "Who is captain of the team?"
*Noun clause: She asked "who the captain of the team is".
She asked something. The captain of the team is John.
*Interrogative: She asked, "Who is captain of the team?"
*Noun clause: She asked "who the captain of the team is".
Ambiguous cases

A problem sometimes arises in constructions like this:

"Beethoven, who you say was a great composer, wrote only one opera."

Use of who here is normal, and to replace it with whom would be grammatically incorrect, since the pronoun is the subject of was, not the object of "say". Nevertheless, whom is quite commonly encountered, and even defended, in sentences of this type. It may arise from confusion with a form like:

"Beethoven, whom you believe a great composer, wrote only one opera."

In this case, whom is used correctly according to the traditional rules, since it is now the object of the verb "believe".
The use of whom in sentences of the first type referred to as "subject whom"can therefore be regarded as a hypercorrection, resulting from awareness of a perceived need to correct who to whom in sentences of the second type. Examples of this apparently ungrammatical usage can be found throughout the history of English. The OED traces it back to the 15thcentury, while Jespersen cites even earlier examples from Chaucer. More examples are given below:

Young Ferdinand, whom they suppose is drown'd,
going to seek the grave / Of Arthur, whom they say is kill'd to-night / On your suggestion.
the rest of their company rescued them, and stood over them fighting till they were come to themselves, all but him whom they thought had been dead;
But if others were involved, it was Harris and Klebold whom students said seemed the tightest, who stood apart from the rest of their clique.
He saith unto them, But whom say ye that I am?

Doubts can also arise in the case of free relative clauses, formed with who, whoever, or whosoever. Modern guides to English usage say that the relative pronoun should take the case appropriate to the relative clause, not the function performed by that clause within an external clause. For example, it is correct to write "I'll talk to whoever will listen.", since whoever is the subject of "will listen". On the other hand, "Whomever you choose will suit me" is correct, since whomever is now the object of "choose".
Similarly:

"Let whoever is without sin cast the first stone."
"Whom you choose will be placed on this list."

In sentences of this type, as with the "subject whom" examples above, use of whom is sometimes found in places where it would not be expected grammatically, due to the relative complexity of the syntax. In fact in Middle English it was standard for the form of the pronoun to depend on the function in the external clause; the modern rule came about through re-analysis of the pronoun as primarily an element of the internal clause.