More information on the importance of ancient Coptic Bible texts:
Coptic codex contains the oldest known copy of any translation of ... the Greek Bible!
Read free online: "Coptic Biblical texts in the dialect of Upper Egypt" by Budge, E. A. Wallis, Sir, 1857-1934
"Contains Coptic versions of the Books of Deuteronomy, Jonah, and the Acts of the Apostles, from the papyrus Codex Oriental no. 7594, and the Book of the Apocalypse from the paper manuscript, Oriental no. 6803."
"The oldest known copy of any translation of ... the Greek Bible."
Includes bibliographical references and indexes
Budge says in the Preface: "The texts in the papyrus Codex are of great importance, for the script in the Greek hand which comes at the end of the Acts of the Apostles proves that the volume cannot have been written later than the middle of the fourth century. Hence it is now certain that copies of some Books of the Old and New Testaments, written in Coptic, were in circulation among the Egyptian Christians early in the first half of this century: and it is legitimate to conclude that the origin of the version itself cannot be placed later than the third century. The Codex is, in fact, the oldest known copy of any translation of any considerable portion of the Greek Bible: indeed it is probably as early as any copy now in existence of any substantial part of the Bible."
That was in the early 20th century. Not long after an incredible discovery was made. In the forward of Crum's thousand-page Coptic Dictionary, we read "...Only in rare instances did a Coptic document preserve a text, or part of a text, whose Greek original was lost, in which case it became the only source..." "All this changed dramatically with the discovery late in 1945 of the Nag Hammadi codices. The discovery consisted of thirteen Coptic codices copied about the middle of the fourth century C.E. (A.D.)..." "Suddenly, learning Coptic became the middle-age crisis of the New Testament and Patristics scholars and produced another language requirement for their doctoral students." "The thirteen codices contained fifty-two tractates, but since six are duplicates, there are only 46 works. All are translations from Greek, and most were composed in the second and third centuries C.E." ~Forward by James M. Robinson (The forward contains many more important details which you may read after purchasing online, as I have done.)
As you can probably (hopefully) see, there is good cause for attention to be paid in this field of study!
If anyone is interested in learning basic Coptic language and grammar, I recommend reading and/or printing the [free] book found online: "Layton, Bentley. Coptic in 20 Lessons: Introduction to Sahidic Coptic With Exercises & Vocabularies. Leuven. Paris and Dudley. Peeters, 2006." which is required for Washington University's "COPTIC 101 A: Introduction to Sahidic Coptic".
Best wishes to all, in and through Christ Jesus!