This article discusses the intricate religio-linguistic links in multiethnic, multi-religion and multi-lingual Singapore, and looks at how language use in religious activities may affect language maintenance. As an ethnographic study, it examines heritage language use in both private and public domains of traditional religious events, in addition to discussing the implications that meaning-making processes involved in religious conversions in multi-faith families have for heritage language maintenance. The study also reveals the family institution as a stronghold where national language policy does not fully penetrate, and argues that the vitality of heritage language may depend on how successfully cultural and religious practices continue to be performed in the heritage languages.