This collection of articles provides a state-of-the-art overview of core issues in second language speech perception and production. Aimed at phoneticians, speech scientists, psycholinguists, applied linguists, and pedagogical specialists, it presents engaging discussions of fundamental problems and controversies within the field, as well as new empirical findings arising from a variety of methodological approaches. Its twenty chapters, inspired by the ground-breaking work of James E. Flege, address such topics as the theoretical underpinnings of second language speech learning; the nature and etiology of foreign accents; the effects of age, experience, and training; speech intelligibility; and the acquisition of vowels, consonants, tone, and prosody.