This book deals with the phenomenon of third language (L3) acquisition. As a research field, L3 acquisition is established as a branch of multilingualism that is concerned with how multilinguals learn additional languages and the role that their multilingual background plays in the process of language learning. The volume points out some current directions in this particular research area with a number of studies that reveal the complexity of multilingual language learning and its typical variation and dynamics. The eight studies gathered in the book represent a wide range of theoretical positions and offer empirical evidence from learners belonging to different age groups, and with varying levels of proficiency in the target language, as w...