The written form is generally believed to have originated in the western Nile Delta.
An alternate hypothesis supported by some scholars is that the various forms of Coptic do not represent speech variation but different orthographic traditions.
[1][4] However, Bohairic has remained in consistent liturgical use through the present in the Coptic Orthodox Church.
Loprieno also holds that ⲃ, ⲇ, and ⲅ held voiced values /b/, /d/, and /g/ respectively, the latter two occurring solely in words borrowed from Greek and in post-nasal position.
[12] Allen considers vowel values to be more difficult to determine, but proposes the following matrix of distinctive features, common to all dialects of Coptic: Allen holds that stress may fall either on the ultimate or penultima.
In recent decades, research on Coptic dialect variance has shifted from a phonological focus (as suggested through orthographic practice) to a morphosyntactic one.