About the Mystery of the Letters the mid-6th century, in which Mar Saba had played an important role. The anonymous author of the treatise declares he was prompted to the study of the secret meanings of the letters by the words of the Apocalypse, "I am the Alpha and Omega", and that he subsequently received a vision about them on Mount Sinai. The author proposes a re-modelled Greek alphabet reduced to 22 letters on the model of the 22 letters of Hebrew (discounting Xi Ξ and Psi Ψ), and with the Hebrew letter names. He then interprets these letters as symbolic figures of 22 works of
Yemenite Hebrew the Qamats () and Tseri (). He argues that the pronunciation of Yemenite Hebrew was not only uninfluenced by Arabic, but it influenced the pronunciation of Arabic by those Jews, despite the Jewish presence in Yemen for over a millennium. Among the dialects of Hebrew preserved into modern times, Yemenite Hebrew is regarded as one of the forms that retains very many features of Hebrew as used in ancient times, particularly Tiberian Hebrew and Mishnaic Hebrew. This perception is motivated in part by the fact that Yemenite Hebrew preserves many consonant sounds represented by individual letters in the Hebrew alphabet