The article studies minority language policy in the situation of an internal division within a speech community. It is based on the example of the Upper Sorbs -- a Slavic minority in Germany. The division within this community is based on language use, the level of assimilation and religion. The Catholic Upper Sorbs have maintained intergenerational transmission of the language, and have a strong identity based on language use and participation in religious life. Most of the Upper Sorbian Protestants have shifted to German. Hence, the Catholic Upper Sorbs perceive themselves as 'real' Sorbs and -- despite the decreasing number of speakers in their community -- their strategy of language maintenance is through isolating themselves from German speakers. The official Sorbian language policy includes language revitalisation to increase the number of Sorbian speakers by creating new speakers of this language through bilingual education. We discuss the conflicting situation when the institutional minority language revitalisation strategy does not fit the internal 'core' community's language maintenance policy. The research was carried out at one of the Upper Sorbian schools with sociolinguistic observations and interviews with pupils from Sorbian-speaking families and with Sorbian learners, and on Sorbian language research revitalisation efforts.