Editing X-bar theory (section)

{{Short description|Linguistics theory about syntax}}
{{Redirect|X'|the sound|velar ejective fricative}}
{{Linguistics}}
In [[linguistics]], '''X-bar theory''' is a model of phrase structure and a theory of syntactic category formation<ref>{{Cite book |url=http://www.oxfordreference.com/view/10.1093/acref/9780199675128.001.0001/acref-9780199675128 |title=The Concise Oxford Dictionary of Linguistics |date=2014-01-01 |publisher=Oxford University Press |isbn=978-0-19-967512-8 |edition=3 |language=en |doi=10.1093/acref/9780199675128.001.0001}}</ref> that proposes a universal schema for how phrases are organized. It suggests that all phrases share a common underlying structure, regardless of their specific category ([[noun phrase]], [[verb phrase]], etc.). This structure, known as the '''X-bar schema''', is based on the idea that every phrase (XP, X phrase) has a [[Head (linguistics)|head]], which determines the type ([[syntactic category]]) of the phrase (X). 

The theory was first proposed by [[Noam Chomsky]] in 1970<ref name="C70">Chomsky, Noam (1970). Remarks on Nominalization. In: R. Jacobs and P. Rosenbaum (eds.) ''Reading in English Transformational Grammar'', 184–221. Waltham: Ginn.</ref> reformulating the ideas of [[Zellig Harris]] (1951<ref name="H51">{{cite book |last=Harris |first=Zellig |title=Methods in Structural Linguistics |publisher=University of Chicago Press |year=1951 |location=Chicago, IL}}</ref>), and further developed by [[Ray Jackendoff]] (1974,<ref name="J74">{{cite book |last=Jackendoff |first=Ray |title=Introduction to the X-bar Convention |publisher=Indiana University Linguistics Club |year=1974 |location=}}</ref> 1977a,<ref name="J77a">{{cite book |last=Jackendoff |first=Ray |title=X-bar-Syntax: A Study of Phrase Structure |publisher=MIT Press |year=1977a |location=Cambridge, MA}}</ref> 1977b<ref name="J77b">Jackendoff, Ray (1977b) Constraints on Phrase Structure Rules, in P. W. Culicover, T. Wasow & A. Akmajian (eds.), ''Formal Syntax'', Academic Press, New York, pp. 249–83.</ref>), along the lines of the theory of [[generative grammar]] put forth in the 1950s by Chomsky.<ref name="C55">{{Cite book |last=Chomsky |first=Noam |title=The Logical Structure of Linguistic Theory |publisher=MIT Press |year=1955 |isbn= |location=Cambridge, MA |page= |language= |id= |quote= |authorlink=}}</ref><ref name="C57">{{Cite book |last=Chomsky |first=Noam |title=Syntactic Structures |publisher=Mouton |year=1957 |isbn= |location=The Hague |page= |language= |id= |quote= |authorlink=}}</ref> It aimed to simplify and generalize the rules of grammar, addressing limitations of earlier phrase structure models. X-bar theory was an important step forward because it simplified the description of sentence structure. Earlier approaches needed many [[phrase structure rules]], which went against the idea of a simple, underlying system for language. X-bar theory offered a more elegant and economical solution, aligned with the thesis of [[generative grammar]].

X-bar theory was incorporated into both transformational and nontransformational theories of syntax, including [[government and binding theory]] (GB), [[generalized phrase structure grammar]] (GPSG), [[lexical-functional grammar]] (LFG), and [[head-driven phrase structure grammar]] (HPSG).<ref>{{Cite book |last=Müller |first=Stefan |url=https://langsci-press.org/catalog/book/287 |title=Grammatical theory: From transformational grammar to constraint-based approaches. |publisher=Language Science Press |year=2020 |isbn=978-3-96110-273-0 |edition=4th revised and extended |pages=75 |language=en |doi=10.5281/zenodo.3992307}}</ref> Although recent work in the [[minimalist program]] has largely abandoned X-bar schema in favor of [[bare phrase structure]] approaches, the theory's central assumptions are still valid in different forms and terms in many theories of minimalist syntax.