Language and multimodal human interaction in context are central in modeling knowledge co-elaboration. Cognitive, linguistic, social, and emotional aspects are closely imbricated within such interaction, and analyses can target individual, small group, organizational, or cultural level phenomena. Given that many research questions in this area lead to crossing boundaries, I argue for both an interdisciplinary and a complex systems approach in constructing a new descriptive model entitled the MULTi-theoretical and Interdisciplinary model of the GRoup And Individual (MULTi-GRAIN). This model allows for the study of different types of unidirectional and bi-directional causality and is meant as a guide for setting up empirical work where emergence is studied in systems of different orders.