Khai: The Bohairic Letter and Its Disputed Origin

Khai is the twenty eighth letter of the Coptic alphabet as Bohairic uses it, and Bohairic is the dialect of the Nile Delta that became and remains the liturgical language of the Coptic Orthodox Church. The letter writes a back fricative made in the throat, and it carries no numeral value. Sahidic, the Upper Egyptian dialect in which most classical Coptic literature survives, does not use the letter at all, which is why the Coptic alphabet is counted as thirty two letters in Bohairic and thirty one in Sahidic. The discrepancy is not a disagreement about the script; it is a straightforward dialect difference, and both counts are correct for the dialect they describe.

The origin of the sign is a different matter and is genuinely unsettled. Khai is conventionally grouped with the letters taken from Demotic, but its relationship to hori, the Coptic letter for h, has been read in more than one way by specialists, and this atlas records that the readings differ rather than choosing between them. What is not in question is the letter working life. A Coptic Orthodox service book uses khai constantly, and any Bohairic text of any length will carry it, so it is among the most familiar letters to a Coptic reader today even though a scholar working on fourth century Sahidic manuscripts will never meet it.