Latin has remained the Roman Catholic Church's official language for canon law, major papal documents, and the church's internal governance for close to two thousand years, even as the everyday language of ordinary Catholic worship shifted decisively toward local vernaculars following the Second Vatican Council's reforms in the 1960s.
The Codex Iuris Canonici, the Catholic Church's body of canon law, is authoritatively promulgated in Latin, with vernacular translations treated as aids to understanding rather than the binding legal text itself, a practice that keeps Latin functionally central to Catholic institutional life even where it is rarely spoken. Major papal documents, including encyclicals, are still customarily issued with an official Latin text alongside vernacular translations, and the Vatican maintains a Latin language office responsible for rendering modern administrative and theological concepts, including contemporary technology and institutions, into classical Latin vocabulary.
The Tridentine Mass, celebrated entirely in Latin, was the standard form of the Roman Catholic liturgy for roughly four centuries following the Council of Trent in the sixteenth century, and it continues to be celebrated today by some communities under permissions the church has granted for its continued limited use alongside the modern vernacular liturgy. Latin's continued institutional role gives the Catholic Church a documentary continuity across language shifts elsewhere in its history that few other global religious institutions can match, since a scholar today can read a papal document from centuries ago in essentially the same official language used for one issued this year.