Pronoun

In linguistics and grammar, a pronoun is a word or a group of words that one may substitute for a noun or noun phrase.
Pronouns have traditionally been regarded as one of the parts of speech, but some modern theorists would not consider them to form a single class, in view of the variety of functions they perform cross-linguistically. An example of a pronoun is "you", which can be either singular or plural. Sub-types include personal and possessive pronouns, reflexive and reciprocal pronouns, demonstrative pronouns, relative and interrogative pronouns, and indefinite pronouns.
The use of pronouns often involves anaphora, where the meaning of the pronoun is dependent on an antecedent. For example, in the sentence That poor man looks as if he needs a new coat, the meaning of the pronoun he is dependent on its antecedent, that poor man.
The adjective form of the word "pronoun" is "pronominal". A pronominal is also a word or phrase that acts as a pronoun. For example, in That's not the one I wanted, the phrase the one is a pronominal.

Theory

Pronoun versus pro-form

Pronoun is a category of words. A pro-form is a type of function word or expression that stands in for another word, phrase, clause or sentence where the meaning is recoverable from the context. In English, pronouns mostly function as pro-forms, but there are pronouns that are not pro-forms and pro-forms that are not pronouns.

	Example	Pronoun	Pro-form
1	It is a good idea.	✓	✓
2	I know the people who work there.	✓	✓
3	Who works there?	✓
4	It is raining.	✓
5	I asked her to help, and she did so right away.		✓
6	JJ and Petra helped, but the others didn't.		✓

Examples are pronouns and pro-forms. In , the pronoun it "stands in" for whatever was mentioned and is a good idea. In , the relative pronoun who stands in for "the people".
Examples are pronouns but not pro-forms. In , the interrogative pronoun who does not stand in for anything. Similarly, in , it is a dummy pronoun, one that does not stand in for anything. No other word can function there with the same meaning; we do not say "the sky is raining" or "the weather is raining".
A prop-word is a word with little or no semantic content used where grammar dictates a certain sentence member, e.g., to provide a "support" on which to hang a modifier. The word most commonly considered as a prop-word in English is one. The prop-word one takes the place of a countable noun in a noun phrase, normally in a context where it is clear which noun it is replacing. For example, in a context in which hats are being talked about, the red one means "the red hat", and the ones we bought means "the hats we bought". The prop-word thus functions somewhat similarly to a pronoun, except that a pronoun usually takes the place of a whole noun phrase
Finally, in , there are pro-forms that are not pronouns. In , did so is a verb phrase that stands in for "helped", inflected from to help stated earlier in the sentence. Similarly, in , others is a common noun, not a pronoun, but the others probably stands in for the names of other people involved, all proper nouns.

Grammar

Pronouns are listed as one of eight parts of speech in The Art of Grammar, a treatise on Greek grammar attributed to Dionysius Thrax and dating from the 2nd century BC. The pronoun is described there as "a part of speech substitutable for a noun and marked for a person." Pronouns continued to be regarded as a part of speech in Latin grammar, and thus in the European tradition generally.
Because of the many different syntactic roles that they play, pronouns are less likely to be a single word class in more modern approaches to grammar.

Linguistics

Linguists in particular have trouble classifying pronouns in a single category, and some do not agree that pronouns substitute nouns or noun categories. Certain types of pronouns are often identical or similar in form to determiners with related meaning; some English examples are given in the table.

	Pronoun	Determiner
Possessive	ours	our freedom
Demonstrative	this	this gentleman
Indefinite	some	some frogs
Negative	none	no information
Interrogative	which	which option

This observation has led some linguists, such as Paul Postal, to regard pronouns as determiners that have had their following noun or noun phrase deleted. Other linguists have taken a similar view, uniting pronouns and determiners into a single class, sometimes called "determiner-pronoun", or regarding determiners as a subclass of pronouns or vice versa. The distinction may be considered to be one of subcategorization or valency, rather like the distinction between transitive and intransitive verbs—determiners take a noun phrase complement like transitive verbs do, while pronouns do not. This is consistent with the determiner phrase viewpoint, whereby a determiner, rather than the noun that follows it, is taken to be the head of the phrase. Cross-linguistically, it seems as though pronouns share 3 distinct categories: point of view, person, and number. The breadth of each subcategory however tends to differ among languages.

Binding theory and antecedents

The use of pronouns often involves anaphora, where the meaning of the pronoun is dependent on another referential element. The referent of the pronoun is often the same as that of a preceding noun phrase, called the antecedent of the pronoun. The grammatical behavior of certain types of pronouns, and in particular their possible relationship with their antecedents, has been the focus of studies in binding, notably in the Chomskyan government and binding theory. In this binding context, reflexive and reciprocal pronouns in English are referred to as anaphors rather than as pronominal elements. Under binding theory, specific principles apply to different sets of pronouns.
In English, reflexive and reciprocal pronouns must adhere to Principle A: an anaphor must be bound in its governing category. Therefore, in syntactic structure it must be lower in structure and have a direct relationship with its referent. This is called a C-command relationship. For instance, we see that John cut himself is grammatical, but Himself cut John is not, despite having identical arguments, since himself, the reflexive, must be lower in structure to John, its referent. Additionally, we see examples like John said that Mary cut himself are not grammatical because there is an intermediary noun, Mary, that disallows the two referents from having a direct relationship.
On the other hand, personal pronouns must adhere to Principle B: a pronoun must be free within its governing category. This means that although the pronouns can have a referent, they cannot have a direct relationship with the referent where the referent selects the pronoun. For instance, John said Mary cut him is grammatical because the two co-referents, John and him are separated structurally by Mary. This is why a sentence like John cut him where him refers to John is ungrammatical.

Binding cross-linguistically

The type of binding that applies to subsets of pronouns varies cross-linguistically. For instance, in German linguistics, pronouns can be split into two distinct categories—personal pronouns and d-pronouns. Although personal pronouns act identically to English personal pronouns, d-pronouns follow yet another principle, Principle C, and function similarly to nouns in that they cannot have a direct relationship to an antecedent.

Antecedents

The following sentences give examples of particular types of pronouns used with antecedents:

Third-person personal pronouns:
* That poor man looks as if he needs a new coat.
* Julia arrived yesterday. I met her at the station.
* When they saw us, the lions began roaring
Other personal pronouns in some circumstances:
* Terry and I were hoping no one would find us.
* You and Alice can come if you like.
Reflexive and reciprocal pronouns:
* Jack hurt himself.
* We were teasing each other.
Relative pronouns:
* The woman who looked at you is my sister.

Some other types, such as indefinite pronouns, are usually used without antecedents. Relative pronouns are used without antecedents in free relative clauses. Even third-person personal pronouns are sometimes used without antecedents —this applies to special uses such as dummy pronouns and generic they, as well as cases where the referent is implied by the context.

English pronouns

English pronouns have often traditionally been classified as different from nouns, but at least one modern grammar defines them as a subclass of nouns.
English personal pronouns have a number of different syntactic contexts and many features:

person ;
number ;
gender

† Rare.
English also has other pronoun types, including demonstrative, relative, indefinite, and interrogative pronouns:

Demonstrative	Relative	Indefinite	Interrogative
this	who / whom / whose	one / one's / oneself	who / whom / whose
these	what	something / anything / nothing	what
that	which	someone / anyone / no one	which
those	that	somebody / anybody / nobody
former / latter