Brief presentation to the Osaka Jogakuin University faculty. Defining by contextualizing. Difference between a field and a discipline. Mobility of the learner rather than of devices is key. This presentation is not about specific mobile-assisted language learning (MALL) techniques; it is about characterizing mobile language learning and placing its practice in its cultural, disciplinary, and temporal contexts. This method can be applied to understand and define technical concepts, academic fields or disciplines.