In this book H.D. Adamson reviews scholarship in sociolinguistics and second language acquisition, comparing theories of variation in first and second-language speech, with special attention to the psychological underpinnings of variation theory. Interlanguage is what second language learners speak. It contains syntactic, morphological and phonological patterns that are not those of either the first or the second language, and which can be analyzed using the principles and techniques of variation theory. Interlanguage Variation in Theoretical and Pedagogical Perspective:

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