Sacred Books and Traditions of the Yezidiz, by Isya Joseph, [1919], at sacred-texts.com
The language of the Yezidis, in common with the Kurds, is Kurdish, which belongs to the Iranian group of the Indo-European or Indo-Germanic stock. This Kurmanji possesses a number of dialects not differing much from one another, except the zaza dialect, which is spoken in eastern Mesopotamia by the Kurds, called Ali Alla. The main characteristic of the Kurmangi are the great brevity of its words and the simplicity of its grammatical forms. It is fairly rich in vowels, and richer in deep gutteral sounds. Though Kurdish is the general language of the Yezidis, their religious mysteries are in Arabic. Both languages are spoken by those living in the Sinjar hills and in Šeiḫan.