Generalized phrase structure grammar


Generalized phrase structure grammar (GPSG) is a framework for describing the
syntax In linguistics, syntax () is the set of rules, principles, and processes that govern the structure of Sentence (linguistics), sentences (sentence structure) in a given Natural language, language, usually including word order. The term ''syntax'' ...

semantics Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another o ...
natural language In neuropsychology Neuropsychology is a branch of psychology. It is concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on ...
s. It is a type of constraint-based
phrase structure grammar The term phrase structure grammar was originally introduced by Noam Chomsky Avram Noam Chomsky (born December 7, 1928) is an American linguist Linguistics is the scientific study of language A language is a structured system ...
. Constraint based grammars are based around defining certain syntactic processes as
ungrammatical In linguistics, grammaticality is determined by the conformity to language usage as derived by the grammar of a particular variety (linguistics), speech variety. The notion of grammaticality rose alongside the theory of generative grammar, the goa ...
for a given language and assuming everything not thus dismissed is grammatical within that language. Phrase structure grammars base their framework on constituency relationships, seeing the words in a sentence as ranked, with some words dominating the others. For example, in the sentence "The dog runs", "runs" is seen as dominating "dog" since it is the main focus of the sentence. This view stands in contrast to dependency grammars, which base their assumed structure on the relationship between a single word in a sentence (the sentence head) and its dependents.


GPSG was initially developed in the late 1970s by
Gerald Gazdar Gerald James Michael Gazdar (born 24 February 1950) is a linguist Linguistics is the scientific study of language A language is a structured system of communication used by humans, including speech (spoken language), gestures (Signed ...
. Other contributors include
Ewan Klein Ewan is an anglicisation of the Scottish Gaelic name, Eòghann. It is possibly a derivative of the Pictish name, ''Vuen'' (or 'Wen'), "born of the mountain." It is most common as a male given name in Scotland and Canada. It is also, less commonly, ...
Ivan Sag Ivan Andrew Sag (November 9, 1949 – September 10, 2013) was an American linguistics, linguist and cognitive science, cognitive scientist. He did research in areas of syntax and semantics as well as work in computational linguistics. Personal lif ...
, and
Geoffrey Pullum Geoffrey Keith Pullum (; born 8 March 1945) is a British-American linguist specialising in the study of English. Since 2007 he has been Professor of General Linguistics at the University of Edinburgh. Pullum is a co-author of '' The Cambridge ...
. Their book ''Generalized Phrase Structure Grammar'', published in 1985, is the main monograph on GPSG, especially as it applies to English syntax. GPSG was in part a reaction against
transformational theories of syntax
transformational theories of syntax
. In fact, the notational extensions to
context-free grammars In formal language theory, a context-free grammar (CFG) is a formal grammar whose Production (computer science), production rules are of the form :A\ \to\ \alpha with A a ''single'' nonterminal symbol, and \alpha a string of Terminal and nontermi ...
(CFGs) developed in GPSG are claimed to make transformations redundant.


One of the chief goals of GPSG is to show that the syntax of natural languages can be described by CFGs (written as
ID/LP grammarID/LP Grammars are a subset of Phrase structure grammar, Phrase Structure Grammars, differentiated from other formal grammars by distinguishing between immediate dominance (ID) and linear precedence (LP) constraints. Whereas traditional phrase struc ...
s), with some suitable conventions intended to make writing such grammars easier for syntacticians. Among these conventions are a sophisticated
feature structureIn phrase structure grammars, such as generalised phrase structure grammar, head-driven phrase structure grammar and lexical functional grammar, a feature structure is essentially a set of attribute–value pairs. For example, the attribute named ''n ...
system and so-called "meta-rules", which are rules generating the productions of a context-free grammar. GPSG further augments syntactic descriptions with semantic annotations that can be used to compute the compositional meaning of a sentence from its syntactic derivation tree. However, it has been argued (for example by
Robert Berwick The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (Hrōþiberhtaz). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of ''Hrōþ, Hruod'' (Old Norse: Hróðr) "fame, glory ...
) that these extensions require
parsing Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other obje ...

algorithms of a higher order of computational complexity than those used for basic CFGs.


There are several ways to represent a sentence in Generalized Phrase Structure Grammar. One such method is a
Syntax treeSyntax tree may refer to: * Abstract syntax tree, used in computer science * Concrete syntax tree, used in linguistics {{dabconcept ...
, which represents all of the words in a sentence as leaf nodes in a parsing tree, as can be seen in the provided image. However, there are several other ways of representing sentences in GPSG. Certain constituents can be illustrated without drawing a full tree by placing the constituent in question inside of brackets like so: Who did you say that Hilary was fond of and [Leslie despised .


Evidence soon emerged, however, that CFGs could not describe all of natural language (with examples in particular from Dutch and Swiss German), and Gazdar, along with most other syntacticians, accepted that natural languages cannot in fact be adequately described by CFGs. As a result, Generalized Phrase Structure Grammar was soon abandoned as a framework for describing natural languages, although CFGs are still used in computing languages. Most of the syntactic innovations of GPSG were subsequently incorporated into head-driven phrase structure grammar.

See also

* Lexical functional grammar *Phrase structure grammar * Transformational grammar *Head-driven phrase structure grammar



External links

Gerald Gazdar's profile on the University of Sussex WebsiteA list of Gazdar's linguistics publications, including ones dealing with GPSG
Generative linguistics Grammar frameworks Syntactic theories Semantic theories