This article focuses mainly on usage of English relative clauses. For theoretical background on the subject, see the main article on relative clause

Relative clause

A relative clause is a subordinate clause that modifies a noun phrase, most commonly a noun. For example, the phrase "the man who wasn't there" contains the noun man, which is modified by the relative clause who wasn't there...

s.

As in many other languages, an English relative clause is a subordinate clause that modifies a noun phrase, most commonly a noun. Relative clauses in English

English language

English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

 often contain a relative pronoun

Relative pronoun

A relative pronoun is a pronoun that marks a relative clause within a larger sentence. It is called a relative pronoun because it relates the relative clause to the noun that it modifies. In English, the relative pronouns are: who, whom, whose, whosever, whosesoever, which, and, in some...

, but (unlike in other Germanic languages

Germanic languages

The Germanic languages constitute a sub-branch of the Indo-European language family. The common ancestor of all of the languages in this branch is called Proto-Germanic , which was spoken in approximately the mid-1st millennium BC in Iron Age northern Europe...

) sometimes the relative pronoun is omitted.

The relative pronouns in English are who, whom, whose, which, and that. What is a compound relative pronoun (also called a fused relative pronoun), including both the antecedent and the relative, and is equivalent to that which; for example, "I did what he desired" means the same as, "I did that which he desired." Whatever and whatsoever are also compound relatives, equivalent to anything that as in I do what(so)ever I want (=I do anything that I want). Whoever, whosoever, and whomever are compound relatives equivalent to anyone who(m) as in Who(so)ever treats me well is my friend (=Anyone who treats me well is my friend) and in I talk to who(m)ever I want to talk to (=I talk to anyone who(m) I want to talk to).

In some contexts, there may be a choice between two or more of these forms. The choice of relative pronoun may carry additional meaning or draw a number of distinctions.

Overview

1. who, which and that are the basic relative pronouns, and can (to a certain extent) be used in the same positions.
2. who can be used only with an antecedent referring to a person; which, referring to a thing; that, referring to either person or thing. ("The man who ..."; "The thing which ..."; "The man/thing that ...".)
3. that can be used only in restrictive relative clauses, while who and which can be used in both restrictive and non-restrictive clauses. ("The man that/who ..."; "The thing that/which ..."; "My friend, who ..."; "My car, which ...".)
4. whom is a variant of who normally used only in formal English, and only when the antecedent's role in the relative clause is as an object — not a subject. ("The man who saw me"; "The man who/whom I saw".)
5. However, when a preposition in the relative clause is fronted — which normally occurs only in formal English — only whom and which can be used. ("The man who/whom/that I spoke to"; formal "The man to whom I spoke" — not *to who or *to that; "The knife which/that I killed him with"; formal "The knife with which I killed him" — not *with that.)
6. The relative pronoun can also be omitted in many circumstances: Specifically, only in a restrictive relative clause ("The man (who) I saw" vs. "My friend, who I saw"); not when the antecedent serves the subject role in the relative clause (approximately, when directly followed by a verb, hence "The man (who) I saw" vs. "The man who saw me"); not with a fronted preposition in formal English ("The man (who) I spoke to" vs. "The man to whom I spoke").
7. whose is different from all the rest in that it indicates that the antecedent has a possessive role in the relative clause. ("The man whose daughter I married".) Informal English tends to avoid whose. (E.g. in place of "I found a car whose battery is dead", people may say "I found this car, and its battery is dead".)
8. Finally, who, which, whom, whose (and what) also have uses as interrogative pronouns, which are often different from their uses as relative pronouns. ("Who is it?"; "Which man just arrived?"; "What is your name?".) In addition, who and what (along with whoever, whatever, etc.) also have uses as compound relative pronouns. ("I know who/what I like" = "I know the people/things that I like"; "What I said is that I'm tired" = "The thing that I said is that I'm tired".) Similarly, in other contexts that is also a demonstrative
   Demonstrative
   In linguistics, demonstratives are deictic words that indicate which entities a speaker refers to and distinguishes those entities from others...
   
    pronoun ("That is correct"), a demonstrative adjective ("That man is my friend") and a complementizer
   Complementizer
   In linguistics , a complementizer is a syntactic category roughly equivalent to the term subordinating conjunction in traditional grammar. For example, the word that is generally called a complementizer in English sentences like Mary believes that it is raining...
   
    ("I said that my name is John").

The above refers to actual usage, as described in standard books on grammar, such as The Cambridge Grammar of the English Language

The Cambridge Grammar of the English Language

The Cambridge Grammar of the English Language is a book that presents a comprehensive descriptive grammar of English. Its primary authors are Rodney Huddleston and Geoffrey K. Pullum. It was published by Cambridge University Press, Cambridge, in 2002.-Reviews:* Aarts, Bas. . Grammatici certant...

. and A Comprehensive Grammar of the English Language. Some prescriptivist

Linguistic prescription

In linguistics, prescription denotes normative practices on such aspects of language use as spelling, grammar, pronunciation, and syntax. It includes judgments on what usages are socially proper and politically correct...

 style guides, such as The Elements of Style

The Elements of Style

The Elements of Style , also known as Strunk & White, by William Strunk, Jr. and E. B. White, is a prescriptive American English writing style guide comprising eight "elementary rules of usage", ten "elementary principles of composition", "a few matters of form", a list of forty-nine "words and...

, propose additional rules concerning which relative pronouns should be used in which circumstances.

Human or non-human

In their choice of relative pronoun, English-speakers will often distinguish between an antecedent that is a human—who(m)—and an antecedent which is a non-human—which. In this regard, English is unique among the Germanic languages

Germanic languages

The Germanic languages constitute a sub-branch of the Indo-European language family. The common ancestor of all of the languages in this branch is called Proto-Germanic , which was spoken in approximately the mid-1st millennium BC in Iron Age northern Europe...

 as far as bound relatives are concerned. However, as regards free relatives, German uses a strikingly similar strategy distinguishing between 'was'/'was(auch)immer' (cf. English 'what'/'what(so)ever') and wer(auch)immer (cf. English who(so)ever; this distinction may be due to French influence, and is clearly related to the distinction between the interrogative words who(m) and which and that between the (s)he pronouns and it(s).

However, this distinction applies only to which and who. The alternative that is found with both human and non-human antecedents. While some writers recommend reserving that for nonhuman antecedents, this does not reflect majority use. Examples can be found in Shakespeare (the man that hath no music in himself), Mark Twain

Mark Twain

Samuel Langhorne Clemens , better known by his pen name Mark Twain, was an American author and humorist...

 (The Man that Corrupted Hadleyburg), and Ira Gershwin

Ira Gershwin

Ira Gershwin was an American lyricist who collaborated with his younger brother, composer George Gershwin, to create some of the most memorable songs of the 20th century....

 (The Man that Got Away

The Man that Got Away

"The Man that Got Away" is a popular song, published in 1953 and was written for the 1954 version of the movie A Star Is Born. The music was written by Harold Arlen, and the lyrics by Ira Gershwin...

).

Although whose, as the possessive form of who, is often reserved for human antecedents, it is commonly found also with nonhuman ones.

Grammatical case

In the Germanic languages, the case

Grammatical case

In grammar, the case of a noun or pronoun is an inflectional form that indicates its grammatical function in a phrase, clause, or sentence. For example, a pronoun may play the role of subject , of direct object , or of possessor...

 of a relative pronoun is generally marked in its form. In English, this survives only in who, which has a possessive case

Possessive case

The possessive case of a language is a grammatical case used to indicate a relationship of possession. It is not the same as the genitive case, which can express a wider range of relationships, though the two have similar meanings in many languages.See Possession for a survey of the different...

 form whose and an objective case form whom. But the form whom is in decline and is now often restricted to formal use.

Since which and that have no possessive forms, whose is now also used for the possessive form of these, or periphrasis

Periphrasis

In linguistics, periphrasis is a device by which a grammatical category or grammatical relationship is expressed by a free morpheme , instead of being shown by inflection or derivation...

 is sometimes employed:

There is an old house in our street, whose roof Jack fixed.

There is an old house in our street, the roof of which Jack fixed.

Restrictive or non-restrictive

The distinction between restrictive

Restrictiveness

In semantics, a modifier is said to be restrictive if it restricts the reference of its head. For example, in "the red car is fancier than the blue one", red and blue are restrictive, because they restrict which cars car and one are referring to...

, or integrated, relative clauses and non-restrictive, or supplementary, relative clauses in English is marked by prosody

Prosody (linguistics)

In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...

 (in speaking) and punctuation (in writing): a non-restrictive relative clause is typically preceded by a pause in speech or a comma in writing, whereas a restrictive clause normally is not. Compare the following sentences, which have two quite different meanings, and correspondingly two clearly distinguished intonation patterns, depending on whether the commas are inserted:
The builder, who erects very fine houses, will make a large profit. (non-restrictive) The builder who erects very fine houses will make a large profit. (restrictive)

The first example, with commas, and with three short intonation curves, contains a non-restrictive relative clause. It refers to a specific builder, and assumes we know which builder is intended. It tells us firstly about his houses, then about his profits. The second example uses a restrictive relative clause. Without the commas, and with a single intonation curve, the sentence states that any builder who builds such houses will make profits.

A simple test is to remove the relative clause. If the underlying meaning of the sentence changes, then it is a restrictive clause. If the clause turns out to have been a supplement to the basic meaning of the sentence, then that means the clause was a non-restrictive clause.

A distinction is also sometimes drawn between that (restrictive) and which (non-restrictive); see "That or which" below.

Restrictive relative clauses are also called defining relative clauses, or identifying relative clauses. Similarly, non-restrictive relative clauses are called non-defining or non-identifying relative clauses. For more information see restrictive clause and the relevant subsection of relative clause

Relative clause

A relative clause is a subordinate clause that modifies a noun phrase, most commonly a noun. For example, the phrase "the man who wasn't there" contains the noun man, which is modified by the relative clause who wasn't there...

.

That or which

The distinction between the relative pronouns that and which to introduce restrictive relative clauses with non-human antecedents is a frequent point of dispute

Disputed English grammar

Disputed English grammar denotes disagreement about whether given constructions constitute correct English. Such disagreements are often quite impassioned...

.

For clarity, we can look at a slightly modified version of the example above:
The building company, which erects very fine houses, will make a large profit. (non-restrictive) The building company that/which erects very fine houses will make a large profit. (restrictive)

Of the two, only which is commonly used in non-restrictive clauses. The dispute concerns restrictive clauses

Restrictiveness

In semantics, a modifier is said to be restrictive if it restricts the reference of its head. For example, in "the red car is fancier than the blue one", red and blue are restrictive, because they restrict which cars car and one are referring to...

: in informal American speech and in formal and informal British English

British English

British English, or English , is the broad term used to distinguish the forms of the English language used in the United Kingdom from forms used elsewhere...

 that or which are both commonly used in these clauses, but in formal American English

American English

American English is a set of dialects of the English language used mostly in the United States. Approximately two-thirds of the world's native speakers of English live in the United States....

, references generally specify only that, or reduction to a zero relative pronoun (see below). This rule was championed in 1926 by H.W. Fowler

Henry Watson Fowler

Henry Watson Fowler was an English schoolmaster, lexicographer and commentator on the usage of the English language...

, who observed, "Some there are who follow this principle now; but it would be idle to pretend that it is the practice either of most or of the best writers." Some academics, such as Stanford linguist Arnold Zwicky, claim it is "a silly idea," but in the U.S., the Chicago Manual of Style

The Chicago Manual of Style

The Chicago Manual of Style is a style guide for American English published since 1906 by the University of Chicago Press. Its 16 editions have prescribed writing and citation styles widely used in publishing...

 and other mainstream references insist on it, and many professional writers adhere to it.

An exception to the proposed rule of avoiding which in a restrictive relative clause occurs when the relative pronoun is the object of a non-stranded preposition; in this case that cannot be used, and which is used, as in That is the problem of which I am speaking.

Zero relative pronoun

English, unlike other West Germanic languages, has a zero

Zero (linguistics)

A zero, in linguistics, is a constituent needed in an analysis but not realized in speech. This implies that there is a lack of an element where a theory would expect one. It is usually written with the symbol "", in Unicode .There are several kind of zeros....

 relative pronoun (denoted below as Ø) — that is, the relative pronoun is only implied and is not explicitly present. It is an alternative to that or who(m) in a restrictive relative clause:

Jack built the house that I was born in.

Jack built the house Ø I was born in.

He is the person who(m) I saw.

He is the person Ø I saw.

Relative clauses headed by zeros are frequently called contact clauses in TEFL contexts. They are also often referred to as "zero clauses".

The zero relative pronoun cannot be the subject of an active voice verb in the relative clause. Thus one must say:

Jack built the house that sits on the hill.

and never

*Jack built the house Ø sits on the hill.

However, the zero relative pronoun can be the subject of a passive

Passive voice

Passive voice is a grammatical voice common in many of the world's languages. Passive is used in a clause whose subject expresses the theme or patient of the main verb. That is, the subject undergoes an action or has its state changed. A sentence whose theme is marked as grammatical subject is...

 verb in the relative clause. In this case, the auxiliary verb

Auxiliary verb

In linguistics, an auxiliary verb is a verb that gives further semantic or syntactic information about a main or full verb. In English, the extra meaning provided by an auxiliary verb alters the basic meaning of the main verb to make it have one or more of the following functions: passive voice,...

 (e.g., "was") must also be removed from the relative clause:

Jack built the house that was sold yesterday.

Jack built the house Ø sold yesterday.

This rule applies regardless of whether the antecedent of the zero relative is an object or a subject in the main clause:

The house that was built in 1970 is Nirmala's favorite.

The house Ø built in 1970 is Nirmala's favorite.

However, when the antecedent is the subject of the main clause, a potentially confusing garden path sentence

Garden path sentence

A garden path sentence is a grammatically correct sentence that starts in such a way that the readers' most likely interpretation will be incorrect; they are lured into an improper parse that turns out to be a dead end. Garden path sentences are used in psycholinguistics to illustrate the fact that...

 such as the following may result:

The horse raced past the barn fell.

which is derived from

The horse that was raced past the barn fell.

Use with preposition

In formal writing, a relative pronoun often appears as the object of a preposition at the beginning of a relative clause. In this case the pronoun will be whom, whose, or which, never that. Since this is usage is formal, it would be unusual to use who, since formally the objective case form whom serves as the object of a preposition.

Jack is the boy with whom Jenny fell in love.

Jack built the house in which I grew up.

Most Germanic languages require this syntax. However, in modern English it is rather more common to place the preposition where the prepositional phrase would be if the clause were an independent clause (usually at the end of the clause), while placing the relative pronoun at the beginning of the clause or omitting it entirely. Various grammarians over the last several hundred years have declared that this preposition-stranding is not considered correct; hence formal language tends to avoid it. However, it has been in widespread use since Old English times, and is normal in colloquial speech. Therefore any of the following might be heard in ordinary speech:

Jack is the boy whom Jenny fell in love with.

Jack is the boy who Jenny fell in love with.

Jack is the boy that Jenny fell in love with.

Jack is the boy Jenny fell in love with.

Note that, as mentioned above, in a dependent-clause-initial prepositional phrase the relative pronoun serving as the object of the preposition can never be that. However, the relative pronoun in the role of object of the preposition can indeed be that if it is placed at the start of the dependent clause while the preposition is detached from it and located at the end of the clause, as in the above example Jack is the boy that Jenny fell in love with.

Summary

The most common distribution of the forms is therefore as follows (though variations may be heard).

	Restrictive		Nonrestrictive
	Human	Nonhuman	Human	Nonhuman
Subject	who, that	which, that	who	which
Object of verb	who, whom, that, Ø	which, that, Ø	who, whom	which
Attached object of preposition	whom	which	whom	which
Detached object of preposition	who, whom, that, Ø	which, that, Ø	who, whom	which
Possessive	whose, of whom	whose, of which	whose, of whom	whose, of which

Nominal relative clauses

English allows what is called a fused or nominal relative clause — a relative clause that does not modify an external noun phrase, and instead has a nominal function fused into it. For example:

What he did is clearly impossible, but I saw him do it.

Here, what he did has the sense of that which he did, i.e. the thing that he did, and functions as the subject of the verb is. Nominal relative clauses are inherently restrictive.

English has a number of fused relative pronouns, such as what, whatever, and whoever, but all can introduce other kinds of clauses as well; what can also introduce interrogative content clause

Content clause

In grammar, a content clause is a subordinate clause that provides content implied by, or commented upon by, its main clause. The term was coined by Otto Jespersen...

s ("I do not know what he did"), for example, and both whatever and whoever can introduce adverbial

Adverbial

In grammar an adverbial is a word or a group of words that modifies or tells us something about the sentence or the verb. The word adverbial is also used as an adjective, meaning 'having the same function as an adverb'...

s ("Whatever he did, he does not deserve this").