The Coptic alphabet have 31 characters derived from both the Greek alphabet and the Demotic cursive hieroglyphic script (marked in green). Unlike the original Greek alphabet, Coptic does not posses -a distinct upper case version of its letters.
Coptic does not have a set transliteration. But since it derived from the Greek alphabet, we can borrow the Greek transliteration with few changes.
The origin for the additional seven characters — shai, fai, xai, hori, cancia, chima and tiei — is from Egyptian hieroglyphs through a mediate cursive form known as Demotic.
Scholars noticed a possible realization of a velar nasal, particularly in Sahidic. The digraph "ⲛⲕ" /nk/ may be interchanged with "ⲛⲅ" at the end of words. According to Vergote, Ernštedt, Loprieno and Kasser, this points to a realization of [ng] or [ŋg], according to Hinze and Worrel [ŋk], and according to Cartreau and Peust simply [ŋ] similar to German nk.
ⲧⲱⲟⲩⲛⲅ(tōoung) “rise yourself” /ˈtownk/ [ˈtowŋg] or [ˈtowŋk] or [ˈtowŋ] from Egyptian dwn.k
The rare digraph "ⲙⲕ" /nk/ is also interchangeable with "ⲙⲅ". According to Peust, this is realized as [mŋ]:
ⲟⲩⲱⲙⲅ(ouōmg) “to eat you” /ˈwomk/ [ˈwomŋ] from Egyptian wnm.k