Universal grammar (UG), in modern linguistics, is the theory of the innate biological component of the language faculty, usually credited to Noam Chomsky. The basic postulate of UG is that there are innate constraints on what the grammar of a possible human language could be. When linguistic stimuli are received in the course of language acquisition, children then adopt specific syntactic rules that conform to UG. The advocates of this theory emphasize and partially rely on the poverty of the stimulus (POS) argument and the existence of some universal properties of natural human languages. However, the latter has not been firmly established.
Other linguists have opposed that notion, arguing that languages are so diverse that the postulated universality is rare. The theory of universal grammar remains a subject of debate among linguists.
Overview
The term "universal grammar" is placeholder for whichever domain-specific features of linguistic competence turn out to be innate. Within generative grammar, it is generally accepted that there must be some such features, and one of the goals of generative research is to formulate and test hypotheses about which aspects those are. In day-to-day generative research, the notion that universal grammar exists motivates analyses in terms of general principles. As much as possible, facts about particular languages are derived from these general principles rather than from language-specific stipulations.
Evidence
The idea that at least some aspects are innate is motivated by poverty of the stimulus arguments. For example, one famous poverty of the stimulus argument concerns the acquisition of yes–no questions in English. This argument starts from the observation that children only make mistakes compatible with rules targeting hierarchical structure even though the examples which they encounter could have been generated by a simpler rule that targets linear order. In other words, children seem to ignore the possibility that the question rule is as simple as "switch the order of the first two words" and immediately jump to alternatives that rearrange constituents in tree structures. This is taken as evidence that children are born knowing that grammatical rules involve hierarchical structure, even though they have to figure out what those rules are.
History Between 1100 and 1400, the theoretical work on matters of language significantly expanded in western Europe, its typical social context being the teaching of grammar, logic, or theology, producing a vast literature on aspects of linguistic theory, such as a 13th-century theory of grammar known in modern times as modism, although no assertions were made in the texts about "a theory of language," as such. While not much work was done on the evolution of languages, Dante and Roger Bacon offered perceptive observations. Bacon had a complex notion of grammar, which ranged from the teaching of elementary Latin through what he termed "rational grammar", to research on the so-called languages of sacred wisdom, i.e. Latin and Greek. Professor of Latin literature Raf Van Rooy quotes Bacon's "notorious" dictum on grammar used to denote regional linguistic variation and notes Bacon's contention that Latin and Greek, although "one in substance," were each characterized by many idioms (idiomata: proprietates). Van Rooy speculates that Bacon's references to grammar concerned a "quasi-universal nature of grammatical categories," whereas his assertions on Greek and Latin were applications of his lingua/idioma distinction rather than a generalizing statements on the nature of grammar. Linguistics professor Margaret Thomas acknowledges that "intellectual commerce between ideas about Universal Grammar and [second language] acquisition is not a late-20th century invention," but rejects as "convenient" the interpretation of Bacon's dictum"Grammar is substantially one and the same in all languages, despite its accidental variations." Bacon in Summa Grammatica (ca. 1240-1250). by generative grammarians as an assertion by the English polymath of the existence of universal grammar.
The concept of a generalized grammar was at the core of the 17th century projects for philosophical languages. An influential work in that time was Grammaire générale by Claude Lancelot and Antoine Arnauld. They describe a general grammar for languages, coming to the conclusion that grammar has to be universal. There is a Scottish school of universal grammarians from the 18th century that included James Beattie, Hugh Blair, James Burnett, James Harris, and Adam Smith, distinguished from the philosophical-language project.
The article on grammar in the first edition of the Encyclopædia Britannica (1771) contains an extensive section titled "Of Universal Grammar."
In the late 19th and early 20th century, Wilhelm Wundt and Otto Jespersen claimed that these earlier arguments were overly influenced by Latin and ignored the breadth of worldwide language real grammar", but reduced it to universal syntactic categories or super-categories, such as number, tenses, etc.
Behaviorists, after the rise of the eponymous theory, advanced the idea that language acquisition, like any other kind of learning, could be explained by a succession of trials, errors, and rewards for success. In other words, children, according to behaviorists, learn their mother tongue by simple imitation, i.e. through listening and repeating what adults say. For example, when a child says "milk" and the mother will smile and give milk to her child, then, as a result, the child will find this outcome rewarding, which enhances the child's language development.Ambridge & Lieven, 2011.
Theories of universal grammar
Within generative grammar, there are a variety of theories about what universal grammar consists of. One notable hypothesis proposed by Hagit Borer holds that the fundamental syntactic operations are universal and that all variation arises from different feature-specifications in the lexicon. On the other hand, a strong hypothesis adopted in some variants of Optimality Theory holds that humans are born with a universal set of constraints, and that all variation arises from differences in how these constraints are ranked. In a 2002 paper, Noam Chomsky, Marc Hauser and W. Tecumseh Fitch proposed that universal grammar consists solely of the capacity for hierarchical phrase structure.
Main hypotheses
In an article entitled "The Faculty of Language: What Is It, Who Has It, and How Did It Evolve?" Hauser, Chomsky, and Fitch present the three leading hypotheses for how language evolved and brought humans to the point where they have a universal grammar.
The first hypothesis states that the faculty of language in the broad sense (FLb) is strictly homologous to animal communication. This means that homologous aspects of the faculty of language exist in non-human animals.
The second hypothesis states that the FLb is a derived and uniquely human adaptation for language. This hypothesis holds that individual traits were subject to natural selection and came to be specialized for humans.
The third hypothesis states that only the faculty of language in the narrow sense (FLn) is unique to humans. It holds that while mechanisms of the FLb are present in both human and non-human animals, the computational mechanism of recursion has evolved recently, and solely in humans.
Presence of creole languages The presence of creole languages is sometimes cited as further support for this theory, especially by Bickerton's language bioprogram theory. Creole languages develop and form when disparate societies with no common language come together and are forced to devise a new system of communication. The system used by the original speakers is typically an inconsistent mix of vocabulary items, known as pidgin. As these speakers' children begin to acquire their first language, they use the pidgin input to effectively create their own original language, known as a creole language. Unlike pidgins, creole languages have native speakers (those with language acquisition from early childhood) and make use of a full, systematic grammar.
Bickerton claims the fact that certain features are shared by virtually all creole languages supports the notion of a universal grammar. For example, their default point of reference in time (expressed by bare verb stems) is not the present moment, but the past. Using pre-verbal auxiliaries, they uniformly express tense, aspect, and mood. Negative concord occurs, but it affects the verbal subject (as opposed to the object, as it does in languages like Spanish). Another similarity among creole languages can be identified in the fact that questions are created simply by changing the intonation of a declarative sentence; not its word order or content.
Opposing this notion, the work by Carla Hudson-Kam and Elissa Newport suggests that creole languages may not support a universal grammar at all. In a series of experiments, Hudson-Kam and Newport looked at how children and adults learn artificial grammars. They found that children tend to ignore minor variations in the input when those variations are infrequent, and reproduce only the most frequent forms. In doing so, the children tend to standardize the language they hear around them. Hudson-Kam and Newport hypothesize that in a pidgin-development situation (and in the real-life situation of a deaf child whose parents are or were disfluent signers), children systematize the language they hear, based on the probability and frequency of forms, and not that which has been suggested on the basis of a universal grammar. Further, they argue, it seems to follow that creole languages would share features with the languages from which they are derived, and thus look similar in terms of grammar.
Many researchers of universal grammar argue against the concept of relexification, i.e. that a language replaces its lexicon almost entirely with that of another. This, they argue, goes against the universalist notions of a universal grammar, which has an innate grammar.
Views and assessments
Recent research has used recurrent neural network architectures (RNNs). McCoy et al. (2018) focused on a strong version of the poverty-of-the-stimulus argument, which claims that language learners require a hierarchical constraint, although they report that a milder version, which only asserts that a hierarchical bias is necessary, is difficult to assess using RNNs because RNNs must possess some biases and the nature of these biases remains "currently poorly understood." They go on to acknowledge that while all the architectures they used had a bias toward linear order and the GRU-with-attention architecture was the only one that overcame this linear bias sufficiently to generalize hierarchically. "Humans certainly could have such an innate constraint."
The empirical basis of poverty-of-the-stimulus arguments has been challenged by Geoffrey Pullum and others, leading to a persistent back-and-forth debate in the language acquisition literature.
Language acquisition researcher Michael Ramscar has suggested that when children erroneously expect an ungrammatical form that then never occurs, the repeated failure of expectation serves as a form of implicit negative feedback that allows them to correct their errors over time, in the way that, for example, children correct grammar generalizations like goed to went through repetitive failure.