This study examined linguistic patterns in the Jewish ultra-Orthodox community in Israel, a group that has rarely been studied from a sociolinguistic perspective. Participants were 92 girls, 10-12 years old, who attend a school where Yiddish is the language of instruction and Hebrew, Israel's official language, is studied only in religious contexts. Results show that the girls use and prefer to use Yiddish in most contexts and rate their fluency level higher in Yiddish than in Hebrew. Their appreciation of Yiddish was significantly correlated with negative attitudes toward Hebrew. Relationships with parents had no linguistic effects. Findings are discussed in light of the role of both languages in their community, the uniqueness of this linguistic minority group, especially in comparison with immigrants, the impact of group ideology, and the relevance of emotional correlates of language usage at both individual and community levels. (Contains 2 tables and 4 notes.)