Considered an extinct language, the Coptic language is believed to exist only in the liturgical language of the Coptic Church in Egypt. The ancient language that lost in prominence thanks largely to the Arab incursion into Egypt over 1300 years ago remains the spoken language of the church and only two families in Egypt.
Coptic is a combination of the ancient Egyptian languages Demotic, Hieroglyphic and Hieratic, and was the language used by the Ptolemaic rulers of Egypt following the spread of Greek culture throughout much of the Near East. In essence, it is the language of the ancient Egyptians themselves.
Why did they stop speaking Coptic?
With the Arab conquest, Arabic began to be the language spoken in everyday life. After a period of religious turmoil in Egypt, Coptic leaders decided to use Arabic as their main means of conversation in order to show the Arab rulers that they were not conspirators of the European Crusaders.
Probably a good strategy even today, meaning it probably wil go the way of Latin.