This thesis studies second language development in various learning contexts, with a particular emphasis on study-abroad language learning. Second language learning contexts (e.g., regular classroom, study abroad, and domestic immersion) vary widely in terms of quality, quantity, and type of language exposure as well as opportunities for interaction. This variation may inevitably contribute to diversity in L2 development trajectories.
We carried out empirical investigations that zoomed in on listening comprehension, which is the least researched area in the field of second language acquisition research. Results show that knowledge and processing aspects of L2 proficiency may not be equally affected by learning context. At-home learning contexts seem to have limited effect on facilitating language processing efficiency, especially for intermediate-to-advanced learners. Study abroad may be an effective intervention for the acquisition of L2 processing efficiency (speed in particular), but not necessarily for vocabulary acquisition. Furthermore, the relation between individual capacities (e.g., language aptitude) and second language learning seems to be insensitive to learning contexts.
We also investigated the effect of study abroad on second-language development in general, by conducting a systematic review of existing study-abroad research. A multi-level meta-analysis yielded a small-to-medium overall effect of studying abroad on second language development. Further analyses showed that the magnitude of the study-abroad effect was mediated by study characteristics, such as research design and type of measurement, and by length of stay.
All in all, this thesis contributes to our understanding of how learning context and individual capacities are associated with second language learning.