In linguistics, wh-movement (also known as wh-fronting, wh-extraction, or wh-raising) is the formation of syntactic dependencies involving interrogative words. An example in English is the dependency formed between what and the object position of doing in "What are you doing?". Interrogative forms are sometimes known within English linguistics as wh-words, such as what, when, where, who, and why, but also include other interrogative words, such as how. This dependency has been used as a diagnostic tool in syntactic studies as it can be observed to interact with other grammatical constraints.
In languages with wh-movement, sentences or clauses with a wh-word show a non-canonical word order that places the wh-word (or phrase containing the wh-word) at or near the front of the sentence or clause ("Whom are you thinking about?") instead of the canonical position later in the sentence ("I am thinking about you"). Leaving the wh-word in its canonical position is called wh-in-situ and in English occurs in echo questions and polar questions in informal speech.
Wh-movement is one of the most studied forms of linguistic discontinuity.Accounts of wh-fronting appear in many textbooks on syntax and grammar, e.g., Stockwell (1977:35ff.), Baker (1978:119ff.), Riemsdijk and Williams (1986:19ff.), Borsley (1988:188ff.), Radford (1997:267ff.), Roberts (1999:35ff.), Tallerman (2005:217ff.), Carnie (2013, ch.12.3, pp.357ff.). It is observed in many languages and plays a key role in the theories of long-distance dependencies.
The term wh-movement stemmed from early generative grammar in the 1960s and 1970s and was a reference to the theory of transformational grammar, in which the interrogative expression always appears in its canonical position in the deep structure of a sentence but can move leftward from that position to the front of the sentence/clause in the surface structure.For early accounts of question formation and wh-movement, see, for instance, Ross (1967/86:18ff.), Bach (1974:129), Culicover (1976:73f.), Stockwell (1977:172f.), Baker (1978:121f.). Although other theories of syntax do not use the mechanism of movement in the transformative sense, the term wh-movement (or equivalent terms, such as wh-fronting, wh-extraction, or wh-raising) is widely used to denote the phenomenon, even in theories that do not model long-distance dependencies as a movement.
Basic examples The following examples of sentence pairs illustrate wh-movement in main clauses in English: each (a) example has the canonical word order of a declarative sentence in English, while each (b) sentence has undergone wh-movement, whereby the wh-word has been fronted in order to form a direct question.
Wh-fronting of whom, which corresponds to the direct object Tesnière. (1a) Tom has been reading Tesnière. (1b) Whom has Tom been reading?
Wh-fronting of what, which corresponds to the prepositional object syntax. (2a) She should stop talking about syntax. (2b) What should she stop talking about?
Wh-fronting of when, which corresponds to the temporal adjunct tomorrow. (3a) They want to visit us tomorrow. (3b) When do they want to visit us?
Wh-fronting of what, which corresponds to the predicative adjective happy. (4a) She is happy. (4b) What is she?
Wh-fronting of where, which corresponds to the prepositional phrase to school. (5a) She is going to school. (5b) Where is she going?
Wh-fronting of how, which corresponds to the adverb phrase well. (6a) They are doing well. (6b) How are they doing?
These examples illustrate that wh-movement occurs when a constituent is questioned that appears to the right of the finite verb in the corresponding declarative sentence. The main clause remains in V2 word order, with the interrogative fronted to first position while the finite verb stays in second position. Do-support is often needed to enable wh-fronting in such cases, which are reliant on subject–auxiliary inversion.
Subject "fronting" When the subject is questioned, it is unclear whether wh-fronting has occurred because the default position of the subject is clause-initial. In the example sentence pair below, the subject Fred already appears at the front of the sentence where the interrogative is placed.
a. Fred is working hard. b. Who is working hard?
Some theories of syntax maintain that this constitutes a wh-movement, and analyze such cases as if the interrogative subject has moved up the syntactic hierarchy; however, other theories observe that the surface string of words remains the same, and therefore, no movement has occurred.
Distance of movement In many cases, wh-fronting can occur regardless of how far away its canonical location is, as seen in the following set of examples:
a. Whom does Mary like __? b. Whom does Bob know that Mary likes __? c. Whom does Carl believe that Bob knows that Mary likes __?
The interrogative whom is the direct object of the verb like in each of these examples. The dependency relation between the canonical, empty position and the wh-expression appears to be unbounded, in the sense that there is no upper bound on how deeply embedded within the given sentence the empty position may appear.
Wh-expressions without wh-movement Wh-movement typically occurs when forming questions in English. There are certain forms of questions in which wh-movement does not occur (aside from when the question word serves as the subject and so is already fronted):
Echo questions: Speaker confirming what they thought they've heard. You bought what? Quiz questions or specific questions: Asking for detailed specific information. George Orwell was born in which country? Multiple interrogatives in a single sentence. Who bought what? Expected questions: Occur when new information is expected.
Other languages may leave wh-expressions in-situ (in base position) more often, such as Slavic languages. In French, for instance, wh-movement is often optional in certain matrix clauses.Concerning wh-movement in French, see Bošković (2002). Mandarin and Russian also possess wh-expressions without obligatory wh-movement.
In-situ questions are different from wh-fronted questions in that they result from no movement at all, which tends to be morphologically or pragmatically conditioned.
In subordinate clauses The basic examples above demonstrate wh-movement in main clauses in order to form a direct question. Wh-movement can also occur in subordinate clauses, although its behavior in subordinate clauses differs in word order.
In indirect questions In English, wh-movement occurs in subordinate clauses to form an indirect question. While wh-fronting occurs in both direct and indirect questions, there is a key word order difference,Concerning the key word order difference across direct and indirect questions, see for instance Roberts (1997:37) and Groß and Osborne (2009:74ff.), and Carnie (2013:367). as illustrated with the following examples:
a. Fred will ask Jill to leave. b. Whom will Fred ask to leave? – Direct question c. I wonder whom Fred will ask to leave. – Indirect question
a. Sam likes to get news about hurricanes. b. What does Sam like to get news about? – Direct question; do-support introduced c. They asked what Sam likes to get news about. – Indirect question
a. Larry stayed home due to the weather. b. Why did Larry stay home? – Direct question; do-support introduced c. Nobody knows why Larry stayed home. – Indirect question
In indirect questions, while the interrogative is still fronted to the first position of the clause, the subject is instead placed in second position, and the verb appears in third position, forming a V3 word order.
In relative clauses Although many examples of wh-movement form questions, wh-movement also occurs in relative clauses.See Carnie (2013:369ff.) for an analysis of relative clauses in terms of wh-movement. Many relative pronouns in English have the same form as the corresponding interrogative words (which, who, where, etc.). Relative clauses are subordinate clauses, so the same V3 word order occurs.
a. I read Fred's paper. b. Fred's paper, which I read – Wh-fronting in relative clause
a. John likes the governor. b. the governor whom John likes – Wh-fronting in relative clause
a. Fred reads the paper in the coffee shop. b. the coffee shop where Fred reads the paper – Wh-fronting in relative clause
The relative pronouns have fronted in the subordinate clauses of the b. examples. The characteristic V3 word order is obligatory, just as in other subordinate clauses.
Pied-piping Many instances of wh-fronting involve pied-piping, where the word that is moved pulls an entire encompassing phrase to the front of the clause with it. Pied-piping was first identified by John R. Ross in his 1967 dissertation.See Ross's (1967/86:121ff.) original account of pied-piping. For further analyses of pied-piping, see for instance Riemsdijk and Williams (1986:28ff.) and Radford (1997:276ff).
Obligatory pied-piping In some cases of wh-fronting, pied-piping is obligatory, and the entire encompassing phrase must be fronted for the sentence to be grammatically correct. In the following examples, the moved phrase is underlined:
a. Susan is reading Fred's novel. b. Whose novel is Susan reading? – Pied-piping of novel c. *Whose is Susan reading novel? – Sentence is incorrect because pied-piping has not occurred
a. The music is very loud. b. How loud is the music? – Pied-piping of loud c. *How is the music loud? – Sentence is incorrect because pied-piping has not occurred
These examples illustrate that pied-piping is often necessary when the wh-word is inside a noun phrase or adjective phrase. Pied-piping is motivated in part by the barriers and islands to extraction (see below). When the wh-word appears underneath a blocking category or in an island, the entire encompassing phrase must be fronted.
Optional pied-piping There are other cases where pied-piping is optional. In English, this occurs most notably when the fronted word is the object of a prepositional phrase. A formal register will pied-pipe the preposition, whereas more colloquial English prefers to leave the preposition in situ:
a. She revealed her secret to Tom. b. To whom did she reveal her secret? – Pied-piping of preposition associated with a formal register c. Whom did she reveal her secret to? – Pied-piping absent in colloquial English
a. He is hiding behind the red door. b. Behind which door is he hiding? – Pied-piping of preposition associated with a formal register c. Which door is he hiding behind? – Pied-piping of preposition absent in colloquial English; pied-piping of noun door still obligatory
The c. examples are cases of preposition stranding, which is possible in colloquial English but not allowed in many languages that are related to English.Concerning preposition stranding in wh-questions in English, see Roberts (1997:212f) and Radford (1999:278ff.). For instance, preposition stranding is largely absent from many of the other Germanic languages, and it may be completely absent from the Romance languages. Prescriptive grammars often claim that preposition stranding should be avoided in English as well, although it may feel artificial or stilted to a native speaker to move the preposition.
Extraction islands
A syntactic island is a construction from which extracting an element leads to an ungrammatical or marginal sentence. For example:
*What did you wonder whether Lisa invented __?Goodall, G. (Ed.). (2021) The Cambridge Handbook of Experimental Syntax, ch. 9.