Shai: The Coptic Letter Taken from Demotic

Shai is the twenty sixth letter of the Coptic alphabet and the first of the seven brought in from Demotic, the cursive Egyptian script that Coptic was in the process of replacing. It writes the sh sound. Egyptian had that sound and used it constantly; Greek did not have it and had no letter for it, so when Egyptian was written in Greek letters something had to be supplied, and the obvious place to look was the script Egyptian was already written in.

Shai carries no numeral value, and neither does any of the other six Egyptian additions. That is a point worth stating plainly rather than assuming, because the Coptic numerals are the Greek alphabetic numerals borrowed as a complete system, running through three ranks of nine from alpha to the sign for nine hundred, and the Egyptian letters stand outside that system entirely because they were never part of the Greek series the values belong to. It would be an easy error to assume that a letter in an alphabet with numeral values must carry one, and Coptic is a clean demonstration that it need not. Shai is frequent, since the sh sound is common in native Egyptian vocabulary, and it is one of the letters that identifies a page as Coptic at a glance to anyone who knows the Greek alphabet.