Recent research in digital game-based language learning has been encouraging, yet it would benefit from research methods that focus on the gaming processes and second-language development (Larsen-Freeman, 2015) rather than learner/player reflection or individuals' beliefs about the validity of gameplay. This has proven challenging as research methods which provide insight into the gameplay experiences and its many factors are needed. Having the gameplay experience occur extramurally is desirable, but makes the direct observation of the learners' activities by a researcher difficult. For this reason, we suggest approaching digital game-based language learning through complex adaptive systems research (Larsen-Freeman & Cameron, 2008a) and employing Dörnyei's (2014) retrodictive qualitative modeling to capture the complex synchronic and diachronic variability of the learners and their individual nonlinear gaming trajectories with requisite data density and over a considerable period of time. This article draws on a study examining language learners playing the online role-playing game "World of Warcraft" over four months. We will focus on the data collection in this observational study and the methods of analysis of a complex adaptive system, which helped to better understand the role of extramural digital gaming for the purpose of second-language development.