This article reports a study conducted with a rarely studied minority group, the Jewish ultra-Orthodox community in Jerusalem, Israel, an extremely religious group that endorses patterns of voluntary segregation. The segregation of the group explored in the present study involves also a linguistic component: this group uses only Yiddish for daily communication and relates to Hebrew, Israel’s official language, mainly as a sacred tongue. The sample consisted of 56 girls, 20 4th graders and 36 7th graders, who were asked to write a story in Hebrew about a good thing that had happened to them. Analysis revealed developmental changes in most of the linguistic measures examined — text length, language productivity measures, and lexicon. In contrast to baseline studies on mainstream L1 groups, Optional Bound Morphology usage also increased with age. Global structure analysis shows that, beside canonic narratives, the girls’ stories also include script-like reports, eventive narratives, and retellings of traditional Hasidic stories. These findings intertwine in interesting ways with the linguistic and socio-cultural findings of the study to reveal how lexical and syntactic categories develop in a second language in the context of narrative text production.