Innovation in foreign language teaching began in the 19th century and, very rapidly, in the 20th century, leading to a number of different methodologies, sometimes conflicting, each trying to be a major improvement over the last or other contemporary methods. The earliеst applied linguists, such as Jean Manesca, Heinrich Gottfried Ollendorff (1803-1865), Henry Sweet (1845-1912), Otto Jespersen (1860-1943) and Harold Palmer (1877-1949) worked on setting principles and approaches based on linguistic and psychological theories, although they left many of the specific practical details for others to devise. The development of foreign language teaching is not linear. There have been two major branches in the field, empirical and theoretical, which have almost completely-separate histories, with each gaining ground over the other at one point in time or another. Examples of researchers on the empiricist side are Jesperson, Palmer, Leonard Bloomfield who promote mimicry and memorization with pattern drills. These methods follow from the basic empiricist position that language acquisition basically results from habits formed by conditioning and drilling. In its most extreme form, language learning is basically the same as any other learning in any other species, human language being essentially the same as communication behaviors seen in other species. On the other, are Francois Gouin, M.D. Berlitz, Elime de Sauzé, whose rationalist theories of language acquisition dovetail with linguistic work done by Noam Chomsky and others. These have led to a wider variety of teaching methods from grammar-translation, to Gouin's "series method" or the direct methods of Berlitz and de Sauzé. With these methods, students generate original and meaningful sentences to gain a functional knowledge of the rules of grammar. This follows from the rationalist position that man is born to think and language use is a uniquely human trait impossible in other species.
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