It has long been debated that linguistic, personal, and sociocultural gains after studying abroad are entitled to several individual difference (ID) variables (Hessel, 2017), such as cognition (Segalowitz & Freed, 2010), motivation (Hernández, 2010), and personality (Baker-Smemoe et al., 2014). However, there is a dearth of studies looking into the effects of multiple ID variables, such as personality and emotional stability on intercultural competence and social and cultural adaptation of sojourners resulting in increased interaction and hence language gains.

This study aims to investigate the predictive power of multicultural personality, mental well-being, and self-perceived language proficiency on actual language gains and sociocultural adjustment of a large group of sojourners from different L1 backgrounds (n = 250) who spent a semester abroad. It also analyzes the role of cultural proximity by comparing participant development by the host location, such as Anglophone, Baltic, Eastern European, Mediterranean, and Scandinavian countries. All the data analyzed collected twice at pre-departure and post-sojourn utilizing online versions of the short form of the Multicultural Personality Questionnaire (Van Oudenhoven & Van der Zee, 2013), the Warwick-Edinburgh Mental Well-being Scale (Tennant et al., 2007) and the Socio-cultural Adaptation Scale (Ward & Kennedy, 1999). We also collected data concerning self-perceived proficiency and actual English proficiency using the Oxford Quick Placement Test accompanied by a short background questionnaire asking for demographic information and self-rated pre-departure and post-sojourn proficiency in English. All the ID-variable instruments were administered in participants’ L1s. The data from the ID instruments were analyzed through a series of linear mixed effects models to see how fixed (Time) and random (participants) effects interact to predict participant sojourners’ sociocultural adaptation and language gains. The preliminary results suggest that openness to diversity and psychological adjustment are strong predictors of sociocultural adaptation, increased interaction, and significant language gains after a semester abroad.