The purpose of this study was to use an app-embedded survey to profile language learner demographics. 3,759 EFL language learners from primarily eight L1 backgrounds (French, German, Italian, Japanese, Korean, Russian, Spanish, and Thai) responded to the survey embedded within a popular English grammar app that has 500,000 downloads and over 100,000 active users. While presently there is very little concrete research on autonomous mobile language learning, it is hoped that this research will provide a methodological foundation for more in-depth research into learner habits and preferences.