occurs." These have been extended to a variety of traits, such as the phonemes found in languages, the word orders which different languages choose, and the reasons why children exhibit certain linguistic behaviors. Other linguists who have influenced this theory include Richard Montague, who developed his version of this theory as he considered issues of the argument from poverty of the stimulus to arise from the constructivist approach to linguistic theory. The application of the idea of universal grammar to the study of second language acquisition (SLA) is represented mainly in the work of McGill linguist Lydia White. Syntacticians generally hold that there are parametric points of variation between languages, although heated debate occurs over whether UG constraints are essentially universal due to being "hard-wired" (Chomsky's principles and parameters approach), a logical consequence of a specific syntactic architecture (the generalized phrase structure approach) or the result of functional constraints on communication (the functionalist approach). Relation to the evolution of language 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 is recently evolved solely in humans. This is the hypothesis which most closely aligns to the typical theory of universal grammar championed by Chomsky. History The term "universal grammar" predates Noam Chomsky, but pre-Chomskyan ideas of universal grammar are different. For Chomsky, UG is "[the] theory of the genetically based language faculty", which makes UG a theory of language acquisition, and part of the innateness hypothesis. Earlier grammarians and philosophers thought about universal grammar in the sense of a universally shared property or grammar of all languages. The