Mobile technologies enable ubiquitous language learning that complements traditional formal teaching environments. Their availability and functionality have promoted self-directed informal learning that helps optimise the time students are exposed to a foreign language. The recent COVID-19 pandemic caused an abrupt shift from traditional in-person teaching environments to distance learning emergency scenarios. All key stakeholders in language programs (administrators, teachers, and students) were caught off guard and had to scramble to find resources and solutions. At the same time, this situation created opportunities for innovation and transformation in language learning and teaching that could remain and be prolonged once critically reviewed. Within this framework, this volume aims to present different learning environments supported by mobile technology, which could become new opportunities to engage in language learning. This mediating role of mobile technology could help move from isolated personal learning to new learning scenarios whose effectiveness is worth analyzing.