linguistics Linguistics is the scientific study of language. The areas of linguistic analysis are syntax (rules governing the structure of sentences), semantics (meaning), Morphology (linguistics), morphology (structure of words), phonetics (speech sounds ...

, crossover effects are restrictions on possible binding or

coreference In linguistics, coreference, sometimes written co-reference, occurs when two or more expressions refer to the same person or thing; they have the same referent. For example, in ''Bill said Alice would arrive soon, and she did'', the words ''Alice'' ...

that hold between certain

phrase In grammar, a phrasecalled expression in some contextsis a group of words or singular word acting as a grammatical unit. For instance, the English language, English expression "the very happy squirrel" is a noun phrase which contains the adject ...

s and

pronoun In linguistics and grammar, a pronoun (Interlinear gloss, glossed ) 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 part of speech, parts of speech, but so ...

s. Coreference (or coindexation) that is normal and natural when a pronoun follows its antecedent becomes impossible, or at best just marginally possible, when "crossover" is deemed to have occurred, e.g. ''?Who₁ do his₁ friends admire __₁?'' The term itself refers to the traditional transformational analysis of sentences containing leftward movement (e.g.

wh-movement 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 ...

topicalization Topicalization is a mechanism of syntax that establishes an expression as the sentence or clause topic (linguistics), topic by having it appear at the front of the sentence or clause (as opposed to in a canonical position later in the sentence). T ...

), whereby it appears as though the fronted constituent crosses over the expression (usually a pronoun) with which it is coindexed on its way to the front of the clause. Crossover effects are divided into strong crossover (SCO) and weak crossover (WCO). The phenomenon occurs in English and related languages, and it may be present in all natural languages that allow fronting.

Examples

Wh-movement

The following sentences illustrate crossover phenomena related to wh-movement. The a-sentences are questions in which crossover has not occurred and are given here for the sake of comparison, and the b-sentences illustrate crossover - the intentional coreferential reading is unavailable per the leftward movement of the wh-expression. The subscripts mark coindexation (≈coreference); they indicate that the words bearing the subscripts are supposed to refer to the same one person. The gaps in the b-sentences mark the canonical position of the wh-expression (before movement): ::a. Who₁ said he₁ was hungry? – Crossover absent, intentional coreferential reading available ::b. *Who₁ did he₁ say __₁ was hungry? – Crossover present (strong), intentional coreferential reading unavailable ::a. Who₁ did you say __₁ likes his₁ parents? – Crossover absent, intentional coreferential reading available ::b. *Who₁ did you say she₁ likes __₁? – Crossover present (strong), intentional coreferential reading unavailable ::a. Who₁ will call his₁ mother? – Crossover absent, coreferential reading available ::b. ?Who₁ will his₁ mother call __₁? – Crossover present (weak), coreferential reading unlikely ::a. Which student₁ called her₁ instructor? – Crossover absent, coreferential reading available ::b. ?Which student₁ did her₁ instructor call __₁ - Crossover present (weak), coreferential reading unlikely The acceptability contrast here is curious upon first analysis. In both the a- and b-sentences, the order of the wh-expression and the coindexed pronoun is the same, the wh-expression preceding the pronoun. But only the reading indicated with the a-sentences is (fully) possible. The relevant difference is that in the b-sentences, the wh-expression appears to have been moved across the pronoun on its way to the front of the sentence, whereas there is no such crossover in the a-sentences.

Topicalization

The following illustrate crossover effects as a result of

, as per Postal (1993).Postal, P. 1993. Remarks on Weak Crossover Effects. ''Linguistic Inquiry,'' ''2''4 (3): 539-556. Postal suggests the idea of "scope islands" may play a role in the observance of crossover phenomena when operators are not the moving element. In the following examples, this effect is shown; the a) examples do not reveal crossover effects but the b) examples do. The crucial element that divides these essentially minimal pairs is the status of the pronoun, which is in the bracketed constituents below:

a. Sidney₁, I am sure ''his₁ jobis important to ___₁. - no "scope island", intentional coreferential reading available b. *Sidney₁, I am sure our opinion of him₁is important to ___₁. - "scope island" restricts the scope to phrase internal, intentional coreferential reading unlikely a. Ted₁, who₁ I am sure that ''his₁ dismissalhas driven ___₁ mad, … - no "scope island", intentional coreferential reading available b. *Ted₁, who₁ I am sure that our dismissal of him₁has driven ___₁ mad, … - "scope island" restricts the scope to phrase internal, intentional coreferential reading unlikely

The observation to be made is that crossover effects also seem to arise when the pronoun being crossed over is embedded in a noun phrase and the item doing the movement is not an operator. The exact factors that play into this observation are under debate - see Comments. These examples belong to the weak crossover category, discussed in detail below.

Strong and weak crossover

As just indicated by the examples, there are two types of crossover, strong and weak. The following two sections consider each of these types.

Strong crossover

Strong crossover occurs when the pronoun is in an argument position, i.e. it is an argument of the relevant verb. This means that it is not contained inside a noun phrase. Instances of strong crossover are clearly impossible, that is, the coreferential reading is strongly unavailable, e.g. ::a. *Which politician₁ did she₁ say that they should vote for __₁? – Strong crossover, intentional coreferential reading impossible ::b. *Who₁ do you think he₁ trusts __₁? – Strong crossover, intentional coreferential reading impossible ::c. *Which man₁ did he₁ promise __₁ would get a promotion? – Strong crossover, intentional coreferential reading impossible While these sentences are actually grammatical, the reading indicated by the subscripts is robustly unavailable. For instance, the first sentence (sentence a) cannot be interpreted to mean that Susan told them to vote for herself (i.e. Susan). Most analyses account for strong crossover effects with Condition C effects of binding theory (see binding for more details). In the underlying structure (before movement) the antecedent (the pronoun) c-commands an

R-expression In Noam Chomsky's government and binding theory in linguistics, an R-expression (short for "referring expression" (''the linked article explains the different, broader usage in other theories of linguistics'') or "referential expression") is a no ...

(the wh-expression) which violates Condition C of binding theory and therefore could explain why a coreferential reading is unavailable in cases of strong crossover. As will be discussed below, the analyses of weak crossover are subject to more debate.

Weak crossover

Crossover is "weak" when the coreferential reading is marginal, that is, when the coreferential reading is not clearly unacceptable, but rather just quite unlikely. Typical cases of weak crossover occur when the expression that has been "crossed over" is a possessor inside a noun phrase, e.g. ::a. ?Which players₁ does their₁ coach distrust __₁? – Weak crossover, indicated reading possible, but unlikely ::b. ?Which beer₁ does its₁ brewer never advertise __₁? – Weak crossover, indicated reading possible, but unlikely ::c. ?Who₁ do her₁ parents worship __₁? – Weak crossover, indicated reading possible, but unlikely The pronoun that has been crossed over in each of these examples is embedded inside a noun phrase. Such cases of crossover are not impossible, but rather just unlikely. Since grammaticality judgments on instances of weak crossover are less robust than strong crossover, much of the literature on crossover effects focuses on weak crossover (see Lasnik & Stowell (1991), Postal (1993), Ruys (2000)) . Koopman & Sportiche (1983) attribute the judgements on coreference with respect to weak crossover to the Bijection Principle: “There is a bijective correspondence between variables and A-positions. (That is, each operator must A-bind exactly one variable, and each variable must be A-bound by exactly one operator.)” In the examples above, neither the trace (T), represented by the gap, nor the pronoun (P) binds the other as the pronoun is contained within a noun phrase. Therefore, the operator locally binds both T and P, meaning that it binds two variables and violates the Bijection Principle. However, weak crossover effects are absent when the pronoun is contained within an adjunct phrase, for example: :a.) Who₁ did you say __₁ was a liar before you met him₁? - Weak crossover absent, coreferential reading possible Based on this observation, Stowell proposes the following analysis of weak crossover: “In a configuration where a quantifier Q locally binds a pronoun P and a trace T, P may not be contained in an argument phrase XP that c-commands T.”Lasnik, H. & Stowell, T. 1991. Weakest Crossover.

Interaction of Weak Crossover with Other Phenomena

There are certain syntactic phenomena in which we would expect weak crossover effects to arise, however we find that they are absent and a coreferential reading is possible, e.g. a.) Parasitic gaps :Who₁ did Susan gossip about __₁ despite his₁ boss having vouched for __₁? b.)

Tough movement Tough may refer to: * Toughness In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing.

Comments

Mechanisms

Crossover is a particular manifestation of binding, which is one of the most explored and discussed areas of theoretical syntax. The factors that determine when the coreferential reading is possible have been extensively debated. Simple linear order plays a role, but the other key factor might be

c-command In generative grammar and related frameworks, a node in a parse tree c-commands its sister node and all of its sister's descendants. In these frameworks, c-command plays a central role in defining and constraining operations such as syntactic movem ...

as associated (primarily) with

government and binding Government and binding (GB, GBT) is a theory of syntax and a phrase structure grammar in the tradition of transformational grammar developed principally by Noam Chomsky in the 1980s. This theory is a radical revision of his earlier theories and wa ...

, or it might be o-command as associated with

head-driven phrase structure grammar Head-driven phrase structure grammar (HPSG) is a highly lexicalized, constraint-based grammar developed by Carl Pollard and Ivan Sag. It is a type of phrase structure grammar, as opposed to a dependency grammar, and it is the immediate successor t ...

. One such analysis (scope-theoretic) of the determining factors for a coreferential reading is outlined by Ruys (2000).Ruys, E. G. 2000. Weak Crossover as a Scope Phenomenon. ''Linguistic Inquiry''. 31 (3): 513–539. doi:10.1162/002438900554424.

ISSN An International Standard Serial Number (ISSN) is an eight-digit to uniquely identify a periodical publication (periodical), such as a magazine. The ISSN is especially helpful in distinguishing between serials with the same title. ISSNs a ...

0024-3892. Therein, crossover phenomena are said to occur when a previous binding/co-indexing relationship between (typically) an operator and a pronoun becomes unavailable after the fronting of a constituent. An operator must take scope over a pronoun in order to bind it; an operator must c-command the pronoun from an argument position (e.g. subject and object position for a verb) at some stage in the derivation in order to have scope over it, according to the theory of syntax adopted in this research. In essence, this requires that an operator c-commands the pronoun from an argument position in order to maintain a coreferential reading with said pronoun; as stated above, this is one side of an ongoing debate.

Universality

Crossover effects, while observed in the manner described in this article in English and related languages, are not exclusively observed in relation to raising or fronting. For example, Yoruba, a language of the Niger-Congo family, does not observe crossover effects in wh-movement examples like the ones given on this page;Adesola, O. 2006. On the Absence of Superiority and Weak Crossover Effects in Yoruba. ''Linguistic Inquiry'', 37 (2): 309-318. expressions such as those are completely grammatical to native speakers. Adesola (2006) describes a process by which Yoruba (and its related languages) avoids crossover effects in wh-movement via null operator raising. This research describes the presence of crossover phenomena elsewhere, however; the implication is that crossover effects may be universal, but are not observed in the same surface structures in all languages.

Notes

References

*Adesola, O. 2006. On the Absence of Superiority and Weak Crossover Effects in Yoruba. ''Linguistic Inquiry'', 37 (2): 309–318. *Lasnik, H. & Stowell, T. 1991. Weakest Crossover. ''Linguistic Inquiry,'' 22(4), pp. 687–720 *Postal, P. 1971. Crossover phenomena. *Postal, P. 1993. Remarks on Weak Crossover Effects. ''Linguistic Inquiry,'' ''2''4 (3): 539–556. *Ruys, E. G. 2000. Weak Crossover as a Scope Phenomenon. ''Linguistic Inquiry''. 31 (3): 513–539. doi:10.1162/002438900554424.

0024-3892. *Wasow, T. 1972. Anaphoric relations in English. MIT dissertation. {{Formal semantics Generative syntax Syntactic relationships Syntax Semantics Formal semantics (natural language)