Second language acquisition is one of the fastest growing disciplines within linguistics, yet few works have explored in depth how a second language is acquired and what the second language learner must do mentally to achieve proficiency in another language. The essays in this book, written by scholars in the field of lingüístics, provide an incisive analysis of these questions. The authors approach second language acquisition from a linguistic rather than a sociological, psychological, or purely pedagogical perspective, representing a wide range of viewpoints and approaches. Applied linguists in particular will find this an extremely valuable resource, as well as general linguistis, graduate students in linguistics, and teachers of foreign languages who want a theoretical base for their work.