X-bar theory is a component of linguistic theory which attempts to identify syntactic features common to all languages. Linguistics is the scientific study of Language, encompassing a number of sub-fields It claims that among their phrasal categories, all languages share certain structural similarities, including one known as the "X-bar", which does not appear in traditional phrase structure rules. Phrase-structure rules are a way to describe a given language's Syntax. X-bar theory was first proposed by Chomsky (1970) and further developed by Jackendoff (1977) . Avram Noam Chomsky (noʊm ˈtʃɑmski born December 7 1928 is an American linguist, Philosopher, cognitive scientist, Political Ray Jackendoff (born January 23, 1945) is an American Linguist.
The letter X is used to signify an arbitrary lexical category; when analyzing a specific utterance, specific categories are assigned. In Grammar, a lexical category (also word class, lexical class, or in traditional grammar part of speech) is a linguistic category of words (or Thus, the X may become an N for noun, a V for verb, an A for adjective, or a P for preposition. For English usage of verbs see the wiki article English verbs. In Grammar, an adjective is a word whose main syntactic role is to modify a Noun or Pronoun, giving more information about the In Grammar, a preposition is a Part of speech that introduces a prepositional phrase.
The term X-bar is derived from the notation representing this new structure. Certain structures are represented by X (an X with an overbar). Because this is difficult to typeset, this is often written as X′, using the prime symbol. In English, however, this is still read as "X bar". The notation XP stands for X Phrase, and is equivalent to X-bar-bar (X with a double overbar), written X″, usually read aloud as X double bar.
There are three "syntax assembly" rules which form the basis of X-bar theory. These rules can be expressed in English, as "rewrite" rules (useful for programmers), or visually as parse trees. A parse tree or concrete syntax tree is an (ordered rooted tree that represents the syntactic structure of a string according to some All three representations are presented below.
1. An X Phrase consists of an optional specifier and an X-bar, in any order:
XP → (specifier), X′
XP XP / \ or / \spec X' X' spec
2. In Syntax, specifier is the sister of X&prime in the X-bar schema of phrase structure seen in the tree diagram below (where XP corresponds to One kind of X-bar consists of an X-bar and an adjunct, in either order:
(X′ → X′, adjunct)
Not all XPs contain X′s with adjuncts, so this rewrite rule is "optional". In Linguistics, an adjunct is any word phrase or clause joined to another word or phrase to qualify or modify it
X' X' / \ or / \ X' adjunct adjunct X'
X′ → X, (complement. In linguistics the head is the word that determines the syntactic type of the Phrase of which it is a member or analogously the stem that determines the In Grammar the term complement is used with different meanings . . )
X' X' / \ or / \ X complement complement X
(a head-first and a head-final example showing one complement)
The following diagram illustrates one way the rules might be combined to form a generic XP structure. Because the rules are recursive, there is an infinite number of possible structures that could be generated, including smaller trees that omit optional parts, structures with multiple complements, and additional layers of XPs and X′s of various types.
XP / \spec X' / \ X' adjunct / \ X complement |head
Because all of the rules allow combination in any order, the left-right position of the branches at any point may be reversed from what is shown in the example. However, in any given language, usually only one handedness for each rule is observed. The above example maps naturally onto the left-to-right phrase order used in English.
Note that a complement-containing X' may be distinguished from an adjunct-containing X' by the fact that the complement has an X (head) as a sister, whereas an adjunct has X-bar as a sister.
The noun phrase "the cat" might be rendered like this:
NP / \ Det N' | | the N | cat
The word the is a determiner (specifically an article), which at first was believed to be a type of specifier for nouns. The head is the determiner (D) which projects into a determiner phrase (DP or DetP). The word cat is the noun phrase (NP) which acts as the complement of the determiner phrase. More recently, it has been suggested that D is the head of the noun phrase.
Note that branches with empty specifiers, adjuncts, complements, and heads are often omitted, to reduce visual clutter. The DetP and NP above have no adjuncts or complements, so they end up being very linear.
In English, specifiers precede the X-bar that contains the head. Thus, determiners always precede their nouns if they are in the same noun phrase. Other languages use different orders. See word order. In Linguistics, word order typology refers to the study of the different ways in which languages arrange the constituents of their sentences relative to each other and the systematic
For more complex utterances, different theories of grammar assign X-bar theory elements to phrase types in different ways. Consider the sentence He studies linguistics at the university. A transformational grammar theory might parse this sentence as the following diagram shows:
The "IP" is an inflectional phrase. In Linguistics, a transformational grammar, or transformational-generative grammar ( TGG) is a Generative grammar, especially of a Natural An inflectional phrase (or IP) is essentially the same as a sentence in which the verb has finite form. Its specifier is the noun phrase (NP) which acts as the subject of the sentence. The complement of the IP is the predicate of the sentence, a verb phrase (VP). In traditional Grammar, a predicate is one of the two main parts of a sentence (the other being the subject, which the predicate modifies There is no word in the sentence which explicitly acts as the head of the inflectional phrase, but this slot is usually considered to contain the unspoken "present tense" implied by the tense marker on the verb "studies".
A head-driven phrase structure grammar might parse this sentence differently. Head-driven phrase structure grammar (HPSG is a highly lexicalized non-derivational Generative grammar theory developed by Carl Pollard and Ivan Sag In this theory, the sentence is modeled as a verb phrase (VP). The noun phrase (NP) that is the subject of the sentence is located in the specifier of the verb phrase. The predicate parses the same way in both theories.
Though X-bar clauses may seem arbitrary and unneeded, their existence can be confirmed by substitution. To the above sentence, "He studies linguistics at the university," someone could reply, "Oh, she does, too. " The word "does," here, stands for the entire V-bar phrase, "studies linguistics at the university", thus implying the existence of this phrase as a complete unit of the whole sentence. In other words: if the V-bar phrase above were not defined as such, the sentence would have three separate phrases directly underneath S: the Noun phrase, the Verb phrase, and the Prepositional phrase. To substitute for two of them, together, as shown, implies that these two, together, make up one phrase within the sentence.
In the mid 1990s, there were two major attempts to deduce versions of X-bar theory from independent principles. The 1990s collectively refers to the years between and including 1990 and 1999 Richard Kayne's theory of Antisymmetry derived X-bar theory from the assumption that there was a tight relation between structure and linear order. Richard Kayne is Professor of Linguistics and current chair of the Linguistics Department at New York University. Antisymmetry is a theory of syntactic linearization presented in Richard Kayne 's 1994 monograph The Antisymmetry of Syntax. Noam Chomsky's paper Bare Phrase Structure attempted to eliminate labelling (i. Avram Noam Chomsky (noʊm ˈtʃɑmski born December 7 1928 is an American linguist, Philosopher, cognitive scientist, Political e. bar-levels) from syntax and deduce their effects from other principles of the grammar.