Over the past few decades perspectives on second language (L2) pronunciation have evolved from pessimistic appraisals of the capabilities of L2 learners and doubts about the value of instruction to a view of pronunciation teaching as an effective and important part of language pedagogy. Earlier research on the teaching of pronunciation dwelt extensively on the identification of learners' errors (mainly consonants and vowels) through comparative analyses. Until recently, little had been established about the effectiveness of pronunciation teaching, and pedagogical techniques were based more on speculation and theoretical notions than on empirically well-justified principles. More recent work addresses a broader range of issues relating not only to L2 phonological acquisition, but to the social implications of speaking with an accent and engaging with interlocutors, both native and non-native speakers of the L2. Among these are the relationship between accent and intelligibility, cognitive processes underlying phonological learning, the evaluation of L2 speech using impressionistic and acoustic techniques, prosodic influences on perception of accented speech, the role of ethnic affiliation and identity in L2 speakers' oral production, and the identification of misguided applications of knowledge about pronunciation by businesses and governments. These lines of work, along with empirical investigations of pronunciation instruction, engender a more sophisticated view of L2 phonological learning and teaching. Though further research remains to be done, important achievements have been made in identifying reasonable, achievable goals in the pronunciation classroom, establishing appropriate instructional foci, and evaluating outcomes. The presenters in this colloquium highlighted the major achievements of recent years and identified some of the important problems that remain.