Learners need diligence when going solo in technology-enhanced learning environments. Nevertheless, self-regulation and scaffolding are two under-researched concepts when it comes to mobile learning. To tackle this knowledge gap, this study focuses on self-regulation and scaffolding for mobile assisted language learning (MALL). Fifty-two students of French as a foreign language were divided into one control and two experimental groups. The two experimental groups were invited to engage in voluntary language learning through a language platform, Duolingo. One of the two experimental groups was trained for self-regulation and received scaffolding for their MALL. The study reveals five main findings: First, students who were trained in self-regulation and received temporary scaffolding present a significantly higher participation in Duolingo. Second, self-regulation features provided by Duolingo are not frequently used by students and therefore do not substantially contribute to students' own learning micromanagement. Third, there is a correlation between high use of Duolingo and improvement in French writing skills. Fourth, just inviting students to engage in voluntary out-of-class MALL does not result in higher test scores for French listening, reading or writing skills. Fifth, in a MALL context, self-regulation training and temporary scaffolding contribute to higher test scores in French writing. Overall, the results suggest that training and scaffolding for self-regulation is beneficial in a voluntary out-of-class MALL context. However, more research is needed to analyze in which conditions voluntary out-of-class MALL can lead to substantial learning improvements.