Migration contributes significantly to the occurrence of language contact and language changes. Migrant communities as diaspora are always faced with choices whether maintaining the use of mother tongue in interacting, switching to using the word of the host, or using ethnic languages side by side with the host language in a new place. This research is intended to provide evidence of the phenomena of communication and social identity focusing on the language use and attitude of diaspora communities in Bali. It is a sociolinguistic study using descriptive qualitative methods on the Muslim community in three regencies that had lived in Bali for more than a generation. The data were collected through questionnaires, in-depth interviews, and direct observation. The result shows that most diaspora communities see the mother tongue as an essential means of maintaining their social identity. From language choice and attitude perspective, the diaspora community leads to three categories, namely (1) the population that identifies themselves as more diaspora than Balinese; (2) the community claiming themselves as more Balinese than diaspora and (3) the community considering themselves as diaspora and Balinese (dual identity).