The Lord’s Prayer, one of the cornerstones of medieval Christian faith, liturgy, and aesthetic creation, is introduced in Mathew 6:5-8. In this passage, Jesus seeks to build a new art of praying, departing both from the performative, collective prayers he associates with synagogal practices and from the praying style of the Gentiles, characterized by unnecessary and audible “babbling” —or βατταλογη, according to the most ancient copy of the Gospel (Codex Sinaiticus, Quire 74, fol.3v). Shedding light on a corpus of Christian —but also lesser-known Jewish devotional poetry mixing Old French, Latin, and/or Hebrew, my talk will illustrate how, in a medieval vernacular French literary culture dominated by its dedication to (Christian) sacredness, this injunction to renounce Jewish modes of worship and “babbling” prayers might have been “lost in translation”. I will argue that these multilingual poems were designed to challenge the listener’s linguistic aptitudes while conjuring various religious and cultural traditions through the combination of languages. Such interlinguistic and interfaith works thus help us reassess prevailing conceptions on the relationship between poetry, devotion, language experimentation, and oral performance in the Middle Ages and beyond.