This book examines the reasons for codeswitching among Indonesian, Javanese and Arabic in religious meetings, called musyawarah, held by the members of an Indonesian Islamic Da wah Association (IIDA) in Malang, East Java, Indonesia. The study is based on the collection and analysis of 13 hours of recording of naturally occurring conversational data, which reflect issues central to the social and religious life of this community. In this context,codeswitching is examined to understand why it occurs, and what it tells us about the social and linguistic interactions occurring in this community. Finally this bookconfirms the hypothesis that codeswitching is used to express the participants unique combined worldview of the Islamic norms and Javanese cultures.