We examine the multilingual situation of the speakers of Mussau-Emira, an Austronesian language spoken in the St Matthias Group of islands of Papua New Guinea. The language repertoire includes Mussau-Emira, the regional language of wider communication Tok Pisin, and English. Within Mussau-Emira, there are currently three closely related dialects spoken on Mussau, and a more distant dialect spoken on Emira. A brief outline of contact with the outside world and traditional trade patterns is given. We look at the current language-use situation, including the use of code-mixing, code-switching and borrowing. Questions of identity are addressed, looking at various layers of identity, based on kinship, geography, and other factors. The changes in the culture due to wider contact, political change and personal mobility are shown to affect several areas of identity. The three Mussau dialects show a remarkable degree of dialect leveling in the course of approximately eighty years. In analyzing this, we see the introduction of Christianity and education with a central boarding school as the key factors in this leveling.