A popular misconception is that Chomsky proved that language is entirely innate, and that he discovered a "universal grammar" (UG). Chomsky simply observed that while a human baby and a kitten are both capable of inductive reasoning, if they are exposed to exactly the same linguistic data, the human will always acquire the ability to understand and produce language, while the kitten will never acquire either ability. Chomsky labeled whatever the relevant capacity the human has that the cat lacks as the language acquisition device (LAD), and he suggested that one of the tasks for linguistics should be to determine what the LAD is and what constraints it imposes on the range of possible human languages. The universal features that would result from these constraints are often termed "universal grammar" or UG.[122] Though Chomsky generated the universal grammar theory with the belief that language is uniquely human, a series of studies from various laboratories have shown the existence of acquired language in several great ape species, including common chimpanzees,[123][124][125][126][127][128][129] bonobos,[129][130] gorillas,[131] and orangutans.[132] Thus, great apes at least partially possess whatever mental functions might underlie the LAD, and are therefore important species of study for exploring the neural basis of language.
Chomsky's ideas have had a strong influence on researchers of language acquisition in children, though many researchers in this area such as Elizabeth Bates[133] and Michael Tomasello[134] argue very strongly against Chomsky's theories, and instead advocate emergentist or connectionist theories, explaining language with a number of general processing mechanisms in the brain that interact with the extensive and complex social environment in which language is used and learned.
Generative grammar
Different grammatical deep structures of a sentence
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Main article: Generative grammar
The Chomskyan approach towards syntax, often termed generative grammar, studies grammar as a body of knowledge possessed by language users. Since the 1960s, Chomsky has maintained that much of this knowledge is innate, implying that children need only learn certain parochial features of their native languages.[135] The innate body of linguistic knowledge is often termed universal grammar. From Chomsky's perspective, the strongest evidence for the existence of Universal Grammar is simply the fact that children successfully acquire their native languages in so little time. Furthermore, he argues that there is an enormous gap between the linguistic stimuli to which children are exposed and the rich linguistic knowledge they attain (the "poverty of the stimulus" argument). The knowledge of Universal Grammar would serve to bridge that gap.
Chomsky's theories have been immensely influential within linguistics, but they have also received criticism. One recurring criticism of the Chomskyan variety of generative grammar is that it is Anglocentric and Eurocentric, and that often linguists working in this tradition have a tendency to base claims about Universal Grammar on a very small sample of languages, sometimes just one. Initially, the Eurocentrism was exhibited in an overemphasis on the study of English. However, hundreds of different languages have now received at least some attention within Chomskyan linguistic analyses.[136][137][138][139][140] In spite of the diversity of languages that have been characterized by UG derivations, critics continue to argue that the formalisms within Chomskyan linguistics are Anglocentric and misrepresent the properties of languages that are different from English.[141][142][143] Thus, Chomsky's approach has been criticized as a form of linguistic imperialism.[144] In addition, Chomskyan linguists rely heavily on the intuitions of native speakers regarding which sentences of their languages are well-formed. This practice has been criticized on general methodological grounds. Some psychologists and psycholinguists,[who?] though sympathetic to Chomsky's overall program, have argued that Chomskyan linguists pay insufficient attention to experimental data from language processing, with the consequence that their theories are not psychologically plausible. Other critics (see language learning) have questioned whether it is necessary to posit Universal Grammar to explain child language acquisition, arguing that domain-general learning mechanisms are sufficient.
Today there are many different branches of generative grammar. One can view grammatical frameworks such as head-driven phrase structure grammar, lexical functional grammar, and combinatory categorial grammar as broadly Chomskyan and generative in orientation, but with significant differences in execution.