Phrase structure grammar

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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 the Chomsky hierarchy: context-sensitive grammars or context-free grammars. In a broader sense, phrase structure grammars are also known as constituency grammars. The defining trait of phrase structure grammars is thus their adherence to the constituency relation, as opposed to the dependency relation of dependency grammars.

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History

In 1956, Chomsky wrote, "A phrase-structure grammar is defined by a finite vocabulary (alphabet) Vp, and a finite set Σ of initial strings in Vp, and a finite set F of rules of the form: X → Y, where X and Y are strings in Vp." [1]

Constituency relation

In linguistics, phrase structure grammars are all those grammars that are based on the constituency relation, as opposed to the dependency relation associated with dependency grammars; hence, phrase structure grammars are also known as constituency grammars. [2] Any of several related theories for the parsing of natural language qualify as constituency grammars, and most of them have been developed from Chomsky's work, including

Further grammar frameworks and formalisms also qualify as constituency-based, although they may not think of themselves as having spawned from Chomsky's work, e.g.

The fundamental trait that these frameworks all share is that they view sentence structure in terms of the constituency relation. The constituency relation derives from the subject-predicate division of Latin and Greek grammars[ citation needed ] that is based on term logic and reaches back to Aristotle [3] in antiquity. Basic clause structure is understood in terms of a binary division of the clause into subject (noun phrase NP) and predicate (verb phrase VP).

The binary division of the clause results in a one-to-one-or-more correspondence. For each element in a sentence, there are one or more nodes in the tree structure that one assumes for that sentence. A two word sentence such as Luke laughed necessarily implies three (or more) nodes in the syntactic structure: one for the noun Luke (subject NP), one for the verb laughed (predicate VP), and one for the entirety Luke laughed (sentence S). The constituency grammars listed above all view sentence structure in terms of this one-to-one-or-more correspondence.

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Dependency relation

By the time of Gottlob Frege, a competing understanding of the logic of sentences had arisen. Frege rejected the binary division of the sentence and replaced it with an understanding of sentence logic in terms of logical predicates and their arguments. On this alternative conception of sentence logic, the binary division of the clause into subject and predicate was not possible. It therefore opened the door to the dependency relation (although the dependency relation had also existed in a less obvious form in traditional grammars long before Frege). The dependency relation was first acknowledged concretely and developed as the basis for a comprehensive theory of syntax and grammar by Lucien Tesnière in his posthumously published work Éléments de syntaxe structurale (Elements of Structural Syntax). [4]

The dependency relation is a one-to-one correspondence: for every element (word or morph) in a sentence, there is just one node in the syntactic structure. The distinction is thus a graph-theoretical distinction. The dependency relation restricts the number of nodes in the syntactic structure of a sentence to the exact number of syntactic units (usually words) that that sentence contains. Thus the two word sentence Luke laughed implies just two syntactic nodes, one for Luke and one for laughed. Some prominent dependency grammars are listed here:

Since these grammars are all based on the dependency relation, they are by definition NOT phrase structure grammars.

Non-descript grammars

Other grammars generally avoid attempts to group syntactic units into clusters in a manner that would allow classification in terms of the constituency vs. dependency distinction. In this respect, the following grammar frameworks do not come down solidly on either side of the dividing line:

See also

Notes

  1. Chomsky, Noam (1956). "Three models for the description of language" (PDF). IRE Transactions on Information Theory : 117.
  2. Matthews (1981:71ff.) provides an insightful discussion of the distinction between constituency- and dependency-based grammars. See also Allerton (1979:238f.), McCawley (1988:13), Mel'cuk (1988:12-14), Borsley (1991:30f.), Sag and Wasow (1999:421f.), van Valin (2001:86ff.).
  3. Bobzien, Susanne. "Ancient Logic". Stanford Encyclopedia of Philosophy. Stanford. Retrieved 4 March 2018.
  4. See Tesnière (1959).

Related Research Articles

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Phrase structure rules are a type of rewrite rule used to describe a given language's syntax and are closely associated with the early stages of transformational grammar, proposed by Noam Chomsky in 1957. They are used to break down a natural language sentence into its constituent parts, also known as syntactic categories, including both lexical categories and phrasal categories. A grammar that uses phrase structure rules is a type of phrase structure grammar. Phrase structure rules as they are commonly employed operate according to the constituency relation, and a grammar that employs phrase structure rules is therefore a constituency grammar; as such, it stands in contrast to dependency grammars, which are based on the dependency relation.

<span class="mw-page-title-main">Parse tree</span> Tree in formal language theory

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In linguistics, X-bar theory is a model of phrase-structure grammar and a theory of syntactic category formation that was first proposed by Noam Chomsky in 1970 reformulating the ideas of Zellig Harris (1951,) and further developed by Ray Jackendoff, along the lines of the theory of generative grammar put forth in the 1950s by Chomsky. It attempts to capture the structure of phrasal categories with a single uniform structure called the X-bar schema, basing itself on the assumption that any phrase in natural language is an XP that is headed by a given syntactic category X. It played a significant role in resolving issues that phrase structure rules had, representative of which is the proliferation of grammatical rules, which is against the thesis of generative grammar.

In linguistics, a verb phrase (VP) is a syntactic unit composed of a verb and its arguments except the subject of an independent clause or coordinate clause. Thus, in the sentence A fat man quickly put the money into the box, the words quickly put the money into the box constitute a verb phrase; it consists of the verb put and its arguments, but not the subject a fat man. A verb phrase is similar to what is considered a predicate in traditional grammars.

Theta roles are the names of the participant roles associated with a predicate: the predicate may be a verb, an adjective, a preposition, or a noun. If an object is in motion or in a steady state as the speakers perceives the state, or it is the topic of discussion, it is called a theme. The participant is usually said to be an argument of the predicate. In generative grammar, a theta role or θ-role is the formal device for representing syntactic argument structure—the number and type of noun phrases—required syntactically by a particular verb. For example, the verb put requires three arguments.

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Dependency grammar (DG) is a class of modern grammatical theories that are all based on the dependency relation and that can be traced back primarily to the work of Lucien Tesnière. Dependency is the notion that linguistic units, e.g. words, are connected to each other by directed links. The (finite) verb is taken to be the structural center of clause structure. All other syntactic units (words) are either directly or indirectly connected to the verb in terms of the directed links, which are called dependencies. Dependency grammar differs from phrase structure grammar in that while it can identify phrases it tends to overlook phrasal nodes. A dependency structure is determined by the relation between a word and its dependents. Dependency structures are flatter than phrase structures in part because they lack a finite verb phrase constituent, and they are thus well suited for the analysis of languages with free word order, such as Czech or Warlpiri.

A sentence diagram is a pictorial representation of the grammatical structure of a sentence. The term "sentence diagram" is used more when teaching written language, where sentences are diagrammed. The model shows the relations between words and the nature of sentence structure and can be used as a tool to help recognize which potential sentences are actual sentences.

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Topicalization is a mechanism of syntax that establishes an expression as the sentence or clause topic by having it appear at the front of the sentence or clause. This involves a phrasal movement of determiners, prepositions, and verbs to sentence-initial position. Topicalization often results in a discontinuity and is thus one of a number of established discontinuity types, the other three being wh-fronting, scrambling, and extraposition. Topicalization is also used as a constituency test; an expression that can be topicalized is deemed a constituent. The topicalization of arguments in English is rare, whereas circumstantial adjuncts are often topicalized. Most languages allow topicalization, and in some languages, topicalization occurs much more frequently and/or in a much less marked manner than in English. Topicalization in English has also received attention in the pragmatics literature.

<span class="mw-page-title-main">Lucien Tesnière</span> French linguist

Lucien Tesnière was a prominent and influential French linguist. He was born in Mont-Saint-Aignan on May 13, 1893. As a senior lecturer at the University of Strasbourg (1924) and later professor at the University of Montpellier (1937), he published many papers and books on Slavic languages. However, his importance in the history of linguistics is based mainly on his development of an approach to the syntax of natural languages that would become known as dependency grammar. He presented his theory in his book Éléments de syntaxe structurale, published posthumously in 1959. In the book he proposes a sophisticated formalization of syntactic structures, supported by many examples from a diversity of languages. Tesnière died in Montpellier on December 6, 1954.

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In linguistics, immediate constituent analysis or IC analysis is a method of sentence analysis that was first mentioned by Leonard Bloomfield and developed further by Rulon Wells. The process reached a full-blown strategy for analyzing sentence structure in the early works of Noam Chomsky. The practice is now widespread. Most tree structures employed to represent the syntactic structure of sentences are products of some form of IC-analysis. The process and result of IC-analysis can, however, vary greatly based upon whether one chooses the constituency relation of phrase structure grammars or the dependency relation of dependency grammars as the underlying principle that organizes constituents into hierarchical structures.

In linguistics, subcategorization denotes the ability/necessity for lexical items to require/allow the presence and types of the syntactic arguments with which they co-occur. For example, the word "walk" as in "X walks home" requires the noun-phrase X to be animate.

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