Manipulation of language is the key to all participation in the legal system. While linguists, especially sociolinguists, have been researching legal contexts for some two decades, there is still a considerable paucity of research on what happens when second language (L2) and second dialect (D2) speakers come into contact with the 'language' of the law. This chapter overviews the current state of theory and research on this topic. As with studies of L1 speakers, most of the studies have analyzed language in courtrooms, where access to data is much easier than in other legal settings, such as police interviews, mediation sessions or lawyer-client interviews. Most such research addresses one or more of the following questions, with the greatest concentration of research on the second and third of these: (a) What are the interpreting needs of second language speakers? (b) How are these needs being addressed? (c) What are the challenges to the provision of language services to second language speakers? And (d) How do dialectal differences affect the participation of second dialect speakers? The discussion concludes by highlighting a number of questions of crucial legal concern that need to be addressed by applied linguistics research.