This article investigates the impact of religion on language. Since religions (or secularisms) are intrinsic parts of human society and communication, every linguistic variety may be analyzed for its religious characteristics and described as a religiolect, a spoken and/or written language variety employed by a religious (or secularized) community, typically of a specific region. Our starting point is an analysis of Jewish-defined languages: wherever Jews have wished to distinguish themselves from their neighbors or have been encouraged or forced to do so, depending on majority-minority dynamics, they developed distinct linguistic elements in their speech and writings. Jewish languages, however, were never an isolated phenomenon. We have tracked several instances where Christians and Muslims have adopted Jewish linguistic usages. Moreover, not only did Christians and Muslims enter the Jewish linguistic spectrum in some places, they also created their own (equally porous) religiolects, or Christian- and Muslim-defined languages. The model of Jewish-defined religiolects can thus be applied to other religious settings, exporting theory developed in a “minority” field to general disciplines or other “minority” fields. This article maps out a prototype of a Jewish-defined language and, most importantly, applies this prototype to Christian- and Muslim-defined languages.