Hori: The Coptic Letter Taken from Demotic

Hori is the twenty ninth letter of the Coptic alphabet and arguably the most important of the seven taken from Demotic. It writes the h sound, which Egyptian used constantly and for which Greek had no letter at all, having long since given up its own h in favour of a breathing mark written above a vowel. Coptic could not manage without it, so a sign was taken from Demotic, and hori carries no numeral value for the same reason as the other Egyptian additions.

Beyond its own frequency in native vocabulary, hori stands behind three of the Greek letters. Theta serves as a compression of tau plus hori, phi of pi plus hori, and khi of kappa plus hori, and in each case Coptic may write the single Greek letter or spell out the two, with manuscripts differing along dialect and workshop lines. That makes hori the hinge of the alphabet: an Egyptian letter against which three of the borrowed Greek letters have to be defined. Whether the compressions are genuine single consonants of Coptic or merely compact spellings of a sequence is a question grammarians have argued, and the evidence is spelling rather than sound, since Sahidic has not been spoken for a thousand years. Either way hori is the letter that makes the question askable.