Following the social turn in Second Language Acquisition (SLA) in the 1990s (Block, 2003), researchers have increasingly focused on the emic perspective of learners. As a result, identity, subjectivity, and agency have come to the forefront in SLA research. In an effort to afford learners the means to negotiate meaning more freely and to position themselves socially through their linguistic choices, Concept-Based Instruction (CBI) has recently gained prominence. A good example is van Compernolle (2012), a study that assessed the outcomes of explicit instruction of the concept of "order of indexicality", and the sub-concepts of "social power", "social distance", and "self-presentation" on the pragmatic awareness of beginning learners of French as a foreign language. Even though participants grasped the sub-concepts, they failed to demonstrate an understanding of the main concept of indexicality. Despite the study's innovative application of CBI to L2 pragmatics, there were several limitations, namely a series of communicative tasks that limited the agentive use of the L2 and a relatively short duration (six weeks) which did not afford participants with the opportunity to dynamically renegotiate their relationship with their interlocutor in role-play. The present study addresses the limitations of van Compernolle (2012), by replicating it and expanding it over an observation period of 15 weeks which comprised 11 weeks during which eight participants took part in an Alternate Reality Game. In lieu of "orders of indexicality", the proposed study included explicit instruction of the concept of "stance taking". In keeping with the tenets of CBI, learners also explored the sociopragmatic constructs of power relations, social distance, and self-presentation through the conceptual lens of stance taking. Following the design and methods of van Compernolle (2012), learners performed communicative tasks such as metalinguistic verbalizations, grammaticality judgments, and role-plays in order to internalize the concept of stance taking. The goal of the ARG implemented in the present study was to promote greater experimentation and language play than possible in the other communicative tasks. The ARG required the learners to engage in regular digitally mediated communication with characters over the period of 11 weeks. Qualitative analyses of the learners' performance data, including their metalinguistic commentary, showed that participants internalized the focal concepts but cited them with various degrees of explicitness during their verbalization. Despite a general absence of language play in participants' performance, they demonstrated agency in their ability to dynamically renegotiate their interactions with their interlocutors in the simulated yet realistic environment of the ARG over time. These findings emphasize the potential of ARGs as ecologically valid possibility spaces for learners to develop their identities and abilities as multicompetent speakers. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]