Finnish and Estonian are relatively closely related languages, which, however, are not considered unconditionally mutually intelligible. The present article discusses the mutual intelligibility of Finnish and Estonian and explores the means by which mutual understanding is created in actual Finnish-Estonian multilingual communication. The data consist of video-recorded informal conversations between Finns and Estonians belonging to a social network in which using both languages (Finnish and Estonian) is a common way of communication. The data are analyzed within the framework of conversation analysis using the concept of participation framework. An overview of informal Finnish- Estonian receptive multilingualism is provided and the language choices are discussed. It is demonstrated that participating in either language does not necessarily cause problems in interaction, and that the shared elements of the languages constitute one resource in creating mutual understanding. However, the participation is also actively facilitated for the participants not competent in both the languages. Receptive multilingualism is shown to be a group phenomenon in the studied data.