Customary societies of Kampung Dukuh is community tightly maintaining their tradition up to the present. It appeared on their life routine beginning from the way of having intercourse, the custom of consuming, the kind of living, the system of leadership until the construction model of stage house constructed from bamboo with palm fiber for the roof. This study aimed to analyze: 1) language dialectic, communication and Sundanese culture at customary society of Kampung Dukuh 2) communication dialectic and tradition of Islam at customary society of Kampung Dukuh 3) Dialectic of Islam tradition and Sundanese culture at customary society of Kampung Dukuh. The method of this research is Ethnography of Communication with qualitative approach. The techniques of data collection are profound interview, participatory observation and documentation research. The results are 1) communication dialectic Sundanese culture lasted in total dialectic manner and indicated relation of dependence each other 2) communication dialectic and tradition of Islam prevailed in total dialectic way, and possessed dependence, affirmed as well as strengthen each other 3) tradition dialectic of Islam and Sundanese culture were divided into two categories namely 1) dialectic of Islam value and culture norm run in total dialectic manner and owned dependence each other 2) dialectic of Islam faith and myths lasted in contradictory way or be in conflict among two different extremes.