Generalized phrase structure grammar (GPSG) is a framework for describing the

syntax In linguistics, syntax ( ) is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure (constituenc ...

and

semantics Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...

natural language A natural language or ordinary language is a language that occurs naturally in a human community by a process of use, repetition, and change. It can take different forms, typically either a spoken language or a sign language. Natural languages ...

s. It is a type of constraint-based

phrase structure grammar The term phrase structure grammar was originally introduced by Noam Chomsky as the term for grammar studied previously by Emil Post and Axel Thue ( Post canonical systems). Some authors, however, reserve the term for more restricted grammars in t ...

. Constraint based grammars are based around defining certain syntactic processes as ungrammatical 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.

Origins

GPSG was initially developed in the late 1970s by Gerald Gazdar. Other contributors include Ewan Klein, Ivan Sag, and

Geoffrey Pullum Geoffrey Keith Pullum (; born 8 March 1945) is a British and American linguist specialising in the study of English. Pullum has published over 300 articles and books on various topics in linguistics, including phonology, morphology, semantics ...

. 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. In fact, the notational extensions to context-free grammars (CFGs) developed in GPSG are claimed to make transformations redundant.

Goals

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 grammar ID/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 stru ...

s), with some suitable conventions intended to make writing such grammars easier for syntacticians. Among these conventions are a sophisticated feature structure 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) that these extensions require

parsing Parsing, syntax analysis, or syntactic analysis is a process of analyzing a String (computer science), string of Symbol (formal), symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal gramm ...

algorithms of a higher order of

computational complexity In computer science, the computational complexity or simply complexity of an algorithm is the amount of resources required to run it. Particular focus is given to computation time (generally measured by the number of needed elementary operations ...

than those used for basic CFGs.

Methodology

There are several ways to represent a sentence in Generalized Phrase Structure Grammar. One such method is a

Syntax tree Syntax tree may refer to: * Abstract syntax tree, used in computer science * Concrete syntax tree, used in linguistics {{Disambig ...

, 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: GPSG_Syntax_Tree_Example

Who did you say that Hilary was fond of and eslie despised .

Counterarguments

Evidence soon emerged, however, that CFGs could not describe all of natural language (with examples in particular from Dutch and Swiss German cross-serial dependencies), 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 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 ...

References

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External links