This thesis offers a sociocritical (Collin, Guichon et Ntébutsé, 2015) and ergonomic (Bertin, 2015; Caws & Hamel, 2016; Rabardel, 1995) analysis of an online language learning activity using Twitter, in order to better understand the complex network of variables influencing the success or failure this digital platform in an educational context. Since the creation of Twitter in 2006, researchers in technology-mediated education have been re-purposing the platform for language learning in order to understand its impact on the learner experience (Hattem & Lomicka, 2016). Most studies investigate the benefits of using Twitter as a way to expose students to real-life social interaction (Reinhardt, 2019); they suggest that this social network motivates students (Albadi, 2016), providing the opportunity for language contextualisation (Antenos-Conforti, 2009), digital literacy development and learner autonomy (Leis, 2014). However, in doing so, many of these studies rely on a deterministic approach, assuming that Twitter has inherent educational potential that can be equally accessed by all students when it is asked of them (Collin et al.). Instead, this thesis deconstructs a network of factors and perceptions acting on a student’s ability and willingness to use Twitter to learn French. In particular, this thesis focuses on the participation and the experience of 10 first-year university French students that were invited to publish tweets and to interact with their peers on Twitter over a period of one semester (12 weeks). Drawing from direct observations, interviews and survey data, the results of my mixed-method case study indicate a possible correlation between learner beliefs, participation, and experience, thus highlighting the importance of designing digital learning activities around the diverse needs and perspectives of learners, rather than the expected outcomes that Twitter can offer. / Graduate