Head-driven phrase structure grammar (HPSG) is a highly lexicalized, non-derivational generative grammar theory 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 to generalized phrase structure grammar. HPSG draws from other fields such as computer science (data type theory and knowledge representation) and uses Ferdinand de Saussure's notion of the sign. It uses a uniform formalism and is organized in a modular way which makes it attractive for natural language processing.
An HPSG grammar includes principles and grammar rules and lexicon entries which are normally not considered to belong to a grammar. The formalism is based on lexicalism. This means that the lexicon is more than just a list of entries; it is in itself richly structured. Individual entries are marked with types. Types form a hierarchy. Early versions of the grammar were very lexicalized with few grammatical rules (schema). More recent research has tended to add more and richer rules, becoming more like Construction Grammar .
The basic type HPSG deals with is the sign. Words and phrases are two different subtypes of sign. A word has two features: (the sound, the phonetic form) and (the syntactic and semantic information), both of which are split into subfeatures. Signs and rules are formalized as typed feature structures.
Read more about Head-driven Phrase Structure Grammar: A Sample Grammar, Implementations
Famous quotes containing the words phrase, structure and/or grammar:
“As if the musicians did not so much play the little phrase as execute the rites required by it to appear, and they proceeded to the necessary incantations to obtain and prolong for a few instants the miracle of its evocation, Swann, who could no more see the phrase than if it belonged to an ultraviolet world ... Swann felt it as a presence, as a protective goddess and a confidante to his love, who to arrive to him ... had clothed the disguise of this sonorous appearance.”
—Marcel Proust (1871–1922)
“The philosopher believes that the value of his philosophy lies in its totality, in its structure: posterity discovers it in the stones with which he built and with which other structures are subsequently built that are frequently better—and so, in the fact that that structure can be demolished and yet still possess value as material.”
—Friedrich Nietzsche (1844–1900)
“Syntax is the study of the principles and processes by which sentences are constructed in particular languages. Syntactic investigation of a given language has as its goal the construction of a grammar that can be viewed as a device of some sort for producing the sentences of the language under analysis.”
—Noam Chomsky (b. 1928)