Research in digital game-based language learning (DGBLL) has shown support for the use of games to develop linguistic knowledge and social skills in the second language (L2) classroom (Cornillie et al., 2012c; Reinhardt, 2019; Sykes & Reinhardt, 2013). Digital games often align with the definition of tasks, but not many have been intentionally explored under a technology-mediated task-based language teaching (TBLT) framework (Gonzalez-Lloret & Ortega, 2014). Additionally, research in second language acquisition (SLA) provides evidence in favor of task-based peer interaction for L2 development, from both sociocultural and interactionist frameworks (Lantolf, 2000; Long, 1996). From a cognitive interactionist perspective, the collaborative dialogue emerging in these interactions provides opportunities for negotiation for meaning, noticing, self-repair, corrective feedback (CF), and other processes facilitative of L2 learning (Gass & Mackey, 2015; Long, 1996). Even though interaction in games is considered one of their main L2 affordances, educational digital games are often designed for single players and few studies have investigated the interaction that occurs during collaborative gaming (e.g., Peterson, 2012; Zheng et al., 2009).There remains a number of under-researched areas in DGBLL. Most research has investigated the impact of gaming on intermediate to advanced language learners after a single gaming session, usually with a pre-treatment-posttest experimental design. Only a few studies have investigated gaming in languages other than English (e.g., Palomo-Duarte et al., 2019; Scholz & Schulz, 2017; Sykes, 2014). Furthermore, few studies have examined L2 development longitudinally (e.g., Piirainen-Marsh & Tainio, 2009; Rama et al., 2012; Sydorenko et al., 2019). Very little is known about how gaming and co-play impacts beginner learners' L2 development. This study addresses these gaps by investigating collaborative and individual gaming of beginner learners of L2 Spanish playing a task-based video game, "Practice Spanish: Study Abroad (PSSA)", at a university program (9 intact classes, N = 156). There were two experimental conditions -- 1) learners played the game individually (n = 53) and 2) learners played in dyads sharing one computer (n = 49) -- and a control group (n = 54), which engaged in technology-mediated activities. This quasi-experimental study used a convenience sample to maintain the ecological validity of the curriculum. The dyad (DYAD) experimental condition engaged in five gaming sessions of "PSSA" in a computer laboratory, while the individual (IND) condition played four quests of "PSSA" at home. All learners completed a pre and post vocabulary and grammar test, and the experimental conditions also completed a self-perceptions questionnaire. The gameplay of five dyads (25 sessions, 17.5 hours) was recorded, transcribed, and coded by type and resolution of language-related episodes (LREs, Swain & Lapkin, 2001), as well as in-game triggers of LREs. Patterns of interaction, strategies used by players, and players' attitudes of engagement and frustration while playing were also examined. The results of the linear-mixed effects models indicate that all learners scored significantly higher in the grammar and vocabulary tests after the semester, but that there were no significant differences between the experimental conditions and the control group. LRE analyses showed all dyads produced many grammatical, lexical, and orthographical LREs. The qualitative analysis of LREs serves to illustrate instances of noticing, hypothesis testing, and peer-feedback. Results also show how game features (e.g., interaction with the game, corrective feedback) triggered interaction. Finally, those playing in dyads displayed more positive attitudes towards the game than individual players based on the end-of-semester questionnaire responses and players engagement during gameplay. This study contributes new knowledge to the field of DGBLL by providing insights into how beginner language learners benefit from playing a task-based digital game. The empirical evidence presented in this study is used to provide recommendations for the implementation of digital games in the L2 curriculum and advice for educational game designers. Research implications are also discussed. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]