Language exposure and use (LEU) are widely viewed as key factors in multilingual development, and research highlights the importance of considering not just the frequency and quantity of LEU, but also contextual factors such as when and where a language is used, with whom and why. In this study, we illustrate the complexity of LEU in two contexts (study abroad and migration) by applying sequential mixture modelling to rich Experience Sampling Method data, considering combinations of various aspects of LEU such as language choice, type of activity, quantity, interlocutor characteristics and learner engagement. We argue that together, these methods for data collection and analysis have the potential to significantly strengthen research into LEU and broader language-related development. By uncovering distinct classes of language-related activities and language user profiles, we gain deeper insight into the nature of situated LEU and its relationship to language development among migrants and in study abroad.