Ancient Egyptians spoke Egyptian, an Afro-Asiatic language. The language originated around 3400 B.C. and continued, in various forms, until the Arab conquest in the 7th century. The national language in modern Egypt is Egyptian Arabic.
While most people associate ancient Egyptians with hieroglyphics, the Egyptian spoken language is equally important. It is one of the oldest recorded languages in history, and was used for over four millenia. The written language did not write vowels, therefore there is no way of knowing how the words in this dead language were ever pronounced.
Coptic, a late variation of Egyptian, is used in the Egyptian Orthodox church liturgy.