Hori ϩ

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.

It is easy to think of a borrowed alphabet as a straightforward gain, and mostly it was, but Greek brought its own gaps. Greek had once had a letter for h and had discarded it, marking initial aspiration instead with a small hook above the vowel, and by the period when Coptic was formed even that was fading from ordinary practice. Greek had also lost the letter digamma from the spoken alphabet while keeping its numeral value in the sixth place, which is why the Coptic numeral sign sou exists and writes nothing.

Egyptian, meanwhile, was a language with a rich set of consonants made at the back of the mouth and in the throat, several of which Greek had never had. So the alphabet that arrived in Egypt was in one respect over-equipped, with letters for aspirated stops and consonant clusters Egyptian did not need, and in another respect under-equipped, missing an h and several other basic Egyptian consonants. Hori is the answer to the second problem and the seven Demotic letters together are the full answer. The first problem was solved by simply keeping the extra letters and using them for loanwords, numerals and optional compressions. Neither solution is elegant, and both are exactly what happens when a real writing system is put together by people who need it to work rather than designed by anyone.