This work is a detailed documentation of the Neo-Aramaic dialect spoken by Assyrian Christians in the region of Urmi (northwestern-Iran). It consists of four volumes. Volumes 1 and 2 are descriptions of the grammar of the dialect, including the phonology, morphology and syntax. Volume 3 contains a study of the lexicon, consisting of a series of lists of words in various lexical fields and a full dictionary with etymologies. Volume 4 contains transcriptions and translations of oral texts, including folktales and descriptions of culture and history. The Urmi dialect is the most important dialect among the Assyrian Christian communities, since it forms the basis of a widely-used literary form of Neo-Aramaic.