Why is Coptic used as a liturgical language in the Coptic Orthodox Church?

Coptic is used as a liturgical language in the Coptic Orthodox Church because it represents the final stage of the ancient Egyptian language, which was the primary medium of religious and daily life for the population of Egypt at the time of the Arab conquest in the 7th century.12

Following the conquest, Arabic gradually replaced Coptic in everyday use, becoming the common language even among Christian Copts by the 12th century. As the language transitioned out of common usage, it was preserved specifically for religious purposes within the church. Today, the church utilizes the Bohairic dialect of Coptic for its service books—which include liturgies attributed to figures such as St. Mark and St. Cyril of Alexandria—often presented in parallel columns alongside Arabic text. While Arabic is now used for Bible lessons and many hymns, Coptic remains a vital liturgical link to the church's historical and cultural heritage.234