Most available evidence suggests that, when acquiring a new language, our brains make the automatic and unconscious assumption that, at some or all levels, it ‘works’ like one of the languages we already know. Since this is not necessarily the case for all properties, when our mental processor ‘transfers’ the previously acquired language this may have positive or negative (and sometimes downright comical) results with respect to target-like performance. How does the brain determine this source of transfer? Which language should it choose? In second language acquisition this question need not be asked, but what if the learner already speaks more than one language? A majority of the contributions to this special issue of Bilingualism: Language and Cognition deal with these questions, which are inevitably related to cognitive economy: transfer, more often than not, saves our brain a lot of time and effort. Exactly how, and under which criteria, the transfer source selection task is performed is what our colleagues are trying to determine. Inside this issue you will find state-of-the-art research on transfer at the initial stages of third language acquisition and beyond, inspecting a variety of linguistic domains that range from morpho-syntax to the lexicon.
Development, a concept just as important as the initial state, takes a complex yet fascinating turn in third language acquisition. A number of papers in this monograph focus on the diverse paths that the course of language acquisition may take within the sphere of multilingualism: from a look at heritage speakers who embark on relearning their native language to a formidable four-year longitudinal study that tracked the progress of almost one hundred bilingual children as they learnt a third language.
Of course, there is room for doubt in this special issue. One of the contributions poses the sensible question of whether studying how third language learners process language will teach us anything we cannot find out by looking at second language speakers. Is there really a qualitative difference between second and third language processing, or is it just more balls to juggle? The answer is as multifaceted as the question itself, but it has great implications for the way in which our brain deals with language.
Ever wondered what we already know about the adventure of learning a third or further language? Come and find out by reading the special issue of Bilingualism here.