Second language acquisition during study abroad (SA) has been a burgeoning field of enquiry over the last three decades. One line of research has investigated students’ social networks. This contribution analyses the longitudinal development of the social interaction network and its influence on L2 gains of 41 U.S. sojourners enrolled in a 3-month intensive study abroad Arabic program. Unlike extant research, the current study i) focuses on students’ interactions with their alma mater classmates as well as other agents ii) reconstructing a complete network of the former, iii) traces the impact of each individual student’s position in the social graph using established centrality metrics, and iv) includes a dynamic developmental perspective with three measurement points at 4-week intervals each, gauging the extent to which changes in the network configuration translate to changes in both self-perceived and objectively measured progress along a range of dimensions.

The learners formed mostly same-gender cliques changing minimally over time. Closeness centrality significantly correlated with TL use and self-perceived gains in linguistic and cultural competence, suggesting communication with classmates might facilitate L2 use and development. The best peer-connected students tended to be highly motivated females with high starting L2 proficiency. Interaction with classmates aligned with initial Arabic proficiency and multilingualism. Motivation to learn Arabic, degree of multilingualism, closeness, and self-reported progress in reading, writing, listening, vocabulary, grammar, and overall Arabic abilities were positively correlated. The strongest predictors of objective proficiency gains were the degree of multilingualism and of closeness to classmates.