“…However, in the present study Duolingo is considered a form of MALL and not of game because the analysis carried out by Gunter, Campbell, Braga, Racilan and Souza (2016) showed that Duolingo does not match the game category, despite presenting features of a game. Culbertson, Wang, Jung and Andersen (2016) suggest that Duolingo uses this game features to keep users engaged according to the RETAIN (Relevance, Embedding, Transfer, Adaptation, Immersion, Naturalization) evaluation model (Gunter;Kenny, & Vick, 2008 cited in Gunter;Campbell;Braga, Racilan, & Souza, 2016). These authors observed the weakest and strongest aspects of this app, though the evaluation was somewhat affected in some points because the model used for the evaluation is meant for analyzing games for educational purposes not and not apps.…”