It is the final stage of the ancient Egyptian language, which was the language of the Egyptians for more than three millennia. All the essential structural aspects of Coptic, the syntax, in particular, are Egyptian. The knowledge of Coptic played a crucial role in the decipherment of the ancient by Jean Francois Champollion (1790-1832). In the Roman period, the first steps were taken to compose an Egyptian text using the alphabet, called Old Coptic by scholars, which was attested from the first to the fourth or fifth century in magical, astrological, and religious texts of pagan origin.

The Coptic alphabet comprised the entire alphabet and several letters derived from the demotic signs; there are six letters in the Sahidic dialect, some other Coptic dialects feature more, and others less. The proportion of words varies from one Coptic text to another; words represent more than 20 percent of some Coptic texts. The translation of the Bible from into Coptic, which occurred probably as early as the third century, played a significant role in the standardization of the spoken language, molding it in a literary style.

Coptic language and Coptic literature are important for biblical and religious studies because the Septuagint and the New Testament were translated into Coptic as early as the third century. Thus, the Coptic version is based on manuscripts that are considerably older than the majority of the extant texts. The Library of Nag Hammadi, written in Coptic, provides the main source of Gnosticism. A number of noncanonical books are preserved only in Coptic or survive only imperfectly apart from this language. Most remarkable are the Gospel of Thomas, the Dialogue of the Savior, and the .

The Arabization, Islamization of Egypt, and the conversion to Islam occurred gradually over centuries. Beginning in the 11th century, Arabic began to replace Coptic. The latest nonliterary evidence for the use of Coptic comes from the 11th and the 12th centuries. By the 13th century Coptic scholars compiled Coptic grammars written in Arabic. Thus, the Coptic gave way to Arabic, which became the language of the Egyptians to the present day. In the 19th and 20th centuries, there was a movement to revive Coptic that has proved unsuccessful.