tradition grew out of a combination of missionary linguistics (whose goal was to translate the Bible) and anthropology. While originally regarded as a sub-field of anthropology in the United States,[20][21] linguistics is now considered a separate scientific discipline in the US, Australia and much of Europe.Edward Sapir, a leader in American structural linguistics, was one of the first who explored the relations between language studies and anthropology. His methodology had strong influence on all his successors. Noam Chomsky's formal model of language, transformational-generative grammar, developed under the influence of his teacher Zellig Harris, who was in turn strongly influenced by Leonard Bloomfield, has been the dominant model since the 1960s.The structural linguistics period was largely superseded in North America by generative grammar in the 1950s and 60s. This paradigm views language as a mental object, and emphasizes the role of the formal modeling of universal and language specific rules. Noam Chomsky remains an important but controversial linguistic figure. Generative grammar gave rise to such frameworks such as Transformational grammar, Generative Semantics, Relational Grammar, Generalized phrase structure grammar, Head-Driven Phrase Structure Grammar(HPSG) and Lexical Functional Grammar (LFG). Other linguists working in Optimality Theory state generalizations in terms of violable constraints that interact with each other, and abandon the traditional rule-based formalism first pioneered by early work in generativist linguistics.Functionalist linguists working in functional grammar and Cognitive Linguistics tend to stress the non-autonomy of linguistic knowledge and the non-universality of linguistic structures, thus differing significantly from the formal approaches.Schools of studyThere are a wide variety of approaches to linguistic study. These can be loosely divided (although not without controversy) into formalist and functionalist approaches. Formalist approaches stress the importance of linguistic forms, and seek explanations for the structure of language from within the linguistic system itself. For example, the fact that language shows recursion might be attributed to recursive rules. Functionalist linguists by contrast view the structure of language as being driven by its function. For example, the fact that languages often put topical information first in the sentence, may be due to a communicative need to pair old information with new information in discourse.Generative grammarMain article: Generative grammarDuring the last half of the 20th century, following the work of Noam Chomsky, linguistics was dominated by the generativist school. While formulated by Chomsky in part as a way to explain how human beings acquire language and the biological constraints on this acquisition, in practice it has largely been concerned with giving formal accounts of specific phenomena in natural languages. Generative theory is modularist and formalist in character. Formal linguistics remains the dominant paradigm for studying linguistics,[22] though Chomsky's writings have also gathered much criticism.Cognitive linguisticsMain article: Cognitive linguisticsIn the 1970s and 1980s, a new school of thought known as cognitive linguistics emerged as a reaction to generativist theory. Led by theorists such as Ronald Langacker and George Lakoff, linguists working within the realm of cognitive linguistics posit that language is an emergent property of basic, general-purpose cognitive processes, though cognitive linguistics has also been the subject of much criticism.[23] In contrast to the generativist