This article presents new data on links between the various medieval vocalisation traditions of Hebrew, Syriac, and Arabic. These include the identification of overlaps in the Aramaic terminology used by Jewish Masoretes and Syriac Christian grammarians and in the phonological theories that underlie them, as well as connections between Syriac and Arabic grammarians. It thus provides evidence that the systems did not develop in isolation, but were the result of intellectual exchanges between various religious communities.