The Mediterranean Sea connected various cultures throughout West Asia,North Africa, and Southern Europe during the Greco-Roman Empire era. Egypt played a central role in Mediterranean Sea culture. The English name Egypt is derived from the ancient Greek Aígyptos. It is located in the center of world trade, transportation between East and West, tourism and academia. The majority of Christian Egyptians have lived near the banks of the Nile River since the first century. The Egyptian Christians are referred to as Copts and use the Coptic language for their religion and social life. Their language and culture reflect their forward-looking, creative, and flourishing spirit during the Roman and Byzantine Empire eras. They were bilingual people who fluently spoke and wrote the Greek and Coptic languages. They were the first to translate Mark's Gospels from Greek to Coptic and also translated the Old and New Testaments. Islam arrived in the 7th century and Egypt emerged as a center of politics and culture in the Muslim world. Copts have been bilingual enough to communicate amongst themselves in the Coptic language and with Muslims in the Arabic language. The Coptic language remained the language of the land, but the Arabic language became the formal and official language of social life. Even now, the Coptic language continues to be the liturgical language in the Coptic Church. Yet Copts have to speak Arabic in daily life. Arabic along with Chinese, English, French, Russian, and Spanish are the six official languages in the United Nations. Arabic is only spoken in the Arab world. However, there are two languages that co-existed with Modern Standard Arabic and spoken Arabic. The most popular spoken language in the Arab world is Egyptian Arabic, because Egypt is the leading country among Arab countries in culture. Coptic Christians speak Arabic with each other about their opinions and feelings. Thus Coptic cultures are explained in Arabic. The purpose of this study is to research how Copts have used the Coptic language during the Greco-Roman Empire era, what role the Coptic language played for Copts in Arabic Islam societies historically, and what the prospects for Copts and the Coptic language will be in 21st century.