بین سالهای ۱۹۲۳ و ۱۹۵۷، هدف زبانشناسی «تکمیل روندهای کشف» بود؛ یعنی یافتن مجموعهای از اصول که زبانشناس را قادر کند تا دستور زبانی را از تودهای اطلاعات که به کمک سخنگوی اهل زبان گفته شده، کشف و استخراج کند و دستور باید علمی باشد و صرفاً براساس الگوهایی باشد که فقط در زبان وجود دارند و هیچ رجوعی به معنا نداشته باشند. به این طریق میتوان به توصیفی عینی و کامل از زبان دست یافت. چامسکی با اعتقاد به اینکه این هدف آرمانگرایانه و محدود است، نقدهایی را بر آن وارد میکند. آرمانگرایانه به این دلیل که امکان ندارد بتوانیم قواعدی خدشهناپذیر برای استخراج یک دستور کامل از تودهای اطلاعات وضع کنیم. محدودیت این دستورها به این دلیل است که از قدرت پیشگویی برخوردار نبودند؛ آنچه را رخ داده بود دستهبندی میکردند و آنچه را ممکن بود رخ دهد پیشگویی نمیکردند. چامسکی معتقد بود دستور باید بهعنوان نظریه یا فرضیهای باشد که چگونگی کارکرد زبان را بیان کند. اگر دستور بهصورت صحیح تدوین شود، به دستگاهی تبدیل میشود که تمام توالیهای دستوری را تولید میکند و هیچ رشتهٔ غیردستوری را پدید نمیآورَد. وظیفهٔ زبانشناس این است که دستورها را فرمولبندی کند تا از این طریق ابزاری برای ارزشیابی دستور فراهم شود و در موقعیتی که زبانشناس با دو دستور روبهرو شد، خود بتواند نوع بهتر را انتخاب کند.
Generative grammar is a linguistic theory that regards grammar as a system of rules that generates exactly those combinations of words that form grammatical sentences in a given language. Noam Chomsky first used the term in relation to the theoretical linguistics of grammar that he developed in the late 1950s. Linguists who follow the generative approach have been called generativists. The generative school has focused on the study of syntax and addressed other aspects of a language's structure, including morphology and phonology.
Early versions of Chomsky's theory were called transformational grammar, a term still used to include his subsequent theories, the most recent of which is the minimalist program theory: Chomsky and other generativists have argued that many of the properties of a generative grammar arise from a universal grammar that is innate to the human brain, rather than being learned from the environment (see the poverty of the stimulus argument).
There are a number of versions of generative grammar currently practiced within linguistics.
A contrasting approach is that of constraint-based grammars. Where a generative grammar attempts to list all the rules that result in all well-formed sentences, constraint-based grammars allow anything that is not otherwise constrained. Certain versions of dependency grammar, head-driven phrase structure grammar, lexical functional grammar, categorial grammar, relational grammar, link grammar, and tree-adjoining grammar are constraint-based grammars that have been proposed. In stochastic grammar, grammatical correctness is taken as a probabilistic variable, rather than a discrete (yes or no) property.
There are a number of different approaches to generative grammar. Common to all is the effort to come up with a set of rules or principles that formally defines each and every one of the members of the set of well-formed expressions of a natural language. The term generative grammar has been associated with at least the following schools of linguistics:
Historical development of models of transformational grammar
Although Leonard Bloomfield, whose work Chomsky rejects, saw the ancient Indian grammarian Pāṇini as an antecedent of structuralism, Chomsky, in an award acceptance speech delivered in India in 2001, claimed "The first generative grammar in the modern sense was Panini's grammar".
Generative grammar has been under development since the late 1950s, and has undergone many changes in the types of rules and representations that are used to predict grammaticality. In tracing the historical development of ideas within generative grammar, it is useful to refer to various stages in the development of the theory.
Standard theory (1957–1965)
The so-called standard theory corresponds to the original model of generative grammar laid out by Chomsky in 1965.
A core aspect of standard theory is the distinction between two different representations of a sentence, called deep structure and surface structure. The two representations are linked to each other by transformational grammar.
Extended standard theory (1965–1973)
The so-called extended standard theory was formulated in the late 1960s and early 1970s. Features are:
Revised extended standard theory (1973–1976)
The so-called revised extended standard theory was formulated between 1973 and 1976. It contains
Relational grammar (ca. 1975–1990)
An alternative model of syntax based on the idea that notions like subject, direct object, and indirect object play a primary role in grammar.
Government and binding/Principles and parameters theory (1981–1990)
Chomsky's Lectures on Government and Binding (1981) and Barriers (1986).
Minimalist program (1990–present)
Generative grammars can be described and compared with the aid of the Chomsky hierarchy (proposed by Chomsky in the 1950s). This sets out a series of types of formal grammars with increasing expressive power. Among the simplest types are the regular grammars (type 3); Chomsky claims that these are not adequate as models for human language, because of the allowance of the center-embedding of strings within strings, in all natural human languages.
At a higher level of complexity are the context-free grammars (type 2). The derivation of a sentence by such a grammar can be depicted as a derivation tree. Linguists working within generative grammar often view such trees as a primary object of study. According to this view, a sentence is not merely a string of words. Instead, adjacent words are combined into constituents, which can then be further combined with other words or constituents to create a hierarchical tree-structure.
The derivation of a simple tree-structure for the sentence "the dog ate the bone" proceeds as follows. The determiner the and noun dog combine to create the noun phrase the dog. A second noun phrase the bone is created with determiner the and noun bone. The verb ate combines with the second noun phrase, the bone, to create the verb phrase ate the bone. Finally, the first noun phrase, the dog, combines with the verb phrase, ate the bone, to complete the sentence: the dog ate the bone. The following tree diagram illustrates this derivation and the resulting structure:
Such a tree diagram is also called a phrase marker. They can be represented more conveniently in text form, (though the result is less easy to read); in this format the above sentence would be rendered as:
Generative grammar has been used to a limited extent in music theory and analysis since the 1980s. The most well-known approaches were developed by Mark Steedman as well as Fred Lerdahl and Ray Jackendoff, who formalized and extended ideas from Schenkerian analysis. More recently, such early generative approaches to music were further developed and extended by various scholars. The theory of generative grammar has been manipulated by the Sun Ra Revival Post-Krautrock Archestra in the development of their post-structuralist lyrics. This is particularly emphasised in their song "Sun Ra Meets Terry Lee". French Composer Philippe Manoury applied the systematic of generative grammar to the field of contemporary classical music.