Adopting a central theme of variability, the book explores different aspects of native and non-native accents of English. The dominating perspective is that of a non-native speaker, although - as argued by some contributors - the very distinction between native and non-native English may need to be redefined. As the debate on the pronunciation of English as a lingua franca continues, this volume presents well-focused studies investigating the acquisition and use of the sound system by native and non-native speakers, problems with the choice and variability in pronunciation models and pedagogical aspects of pronunciation instruction. The issue of accents calls for a comprehensive approach; this book aims to provide such a broad perspective, based on expertise and experience of the contributors, who are specialist in linguitics, applied linguitics, phonetics, phonology and ESL. The book is divided into three parts. Part one discusses complex conditioning of production and perception of native and non-native accents. It contains acoustic and auditory studies investigating the effect of such independent variables as identity, L1 or contextual factors on the elements of the sound system. Part two links the accent variability studies to the pedagogical context by presenting problems with the pronunciation model, its choice and variability. The main focus of part three is on pronunciation teaching: papers presented in this section report on the methods and results of phonetic instruction in different settings.