The Coptic alphabet is variant of the Greek alphabet containing a number of extra letters for sounds not found in Greek. The extra letters come from the Demotic form of the Egyptian script. The Coptic alphabet came into being during the 3rd century BC after the Greek conquest of Egypt and the subsequent spread of Christianity.
The name 'Coptic' derives from the Greek word for Egyptian: Aigyptioi which became Qibt in Arabic and then was Latinised to become Copt
Coptic, a member of the Egyptian branch of the Afro-Asiatic language family and a descendant of the Ancient Egyptian language. Coptic was an official language in Egypt until around the 13th Century AD, when it was replaced by Arabic. Nowadays Coptic Christians all speak Arabic as their every day language, but use Coptic in their religious ceremonies.
About the Copts and the Coptic language
The Coptic Studies Corner
Masters Degree in Coptic Studies at Macquarie University
ALPHABETUM - a Unicode font specifically designed for ancient scripts, including classical & medieval Latin, ancient Greek, Etruscan, Oscan, Umbrian, Faliscan, Messapic, Picene, Iberian, Celtiberian, Gothic, Runic, Old & Middle English, Hebrew, Sanskrit, Old Nordic, Ogham, Kharosthi, Glagolitic, Old Cyrillic, Phoenician, Avestan, Ugaritic, Linear B, Anatolian scripts, Coptic, Cypriot, Brahmi, Old Persian cuneiform: http://guindo.pntic.mec.es/~jmag0042/alphabet.html