This study, the theoretical part of which is based on a longitudinal cross‐linguistic and cross‐behavioral project with Estonian and German immigrants, demonstrates that communication in multilingual settings demands more than the knowledge of several languages. It also demands the control of socio‐culturally conditioned rules of behavior which regulate language use and may vary with the choice of language. In the methodological and theoretical part, it will be shown that the explication of how languages function in different communicative acts requires, instead of the usual language‐oriented approach, an individual‐centered one in which it is necessary to analyze all communicative elements ‐ verbal, paralinguistic, nonverbal and extraverbal ones ‐ from an integrative perspective. The paper further elucidates multilingualism and multiculturalism, interactional competence, models of multilingual communicative behavior, and sources of misunderstanding in intercultural communication and presents cultureme theory as an appropriate research paradigm