There is an emerging trend in higher education for the adoption of massive open online courses (MOOCs). However, despite this interest in learning at scale, there has been limited work investigating how MOOC participants have changed over time. In this study, we explore the temporal changes in MOOC learners’ language and discourse characteristics. In particular, we demonstrate that there is a clear trend within a course for language in discussion forums to be of both more on-topic and reflective of deep learning in subsequent offerings of a course. We measure this in two ways, and demonstrate this trend through several repeated analyses of different courses in different domains. While not all courses show an increase beyond statistical significance, the majority do, providing evidence that MOOC learner populations are changing as the educational phenomena matures.