"The Coptic language uses the indefinite article differently than English, so it does not prove that the Word is in any way not God."
That suggestion is found on certain Trinitarian apologetic sites, but it is inaccurate and demonstrates only a superficial understanding of the Sahidic Coptic language.
The Sahidic Coptic language differs from English only with respect to abstract nouns (i.e, "love," "grace," etc.), not regular common nouns like the Coptic word for "god," which is ΝΟΥΤΕ .
The usage is so similar in English and Coptic grammar that Coptic scholar Thomas O. Lambdin could write: "The use of the Coptic articles, both definite and indefinite, corresponds closely to the use of the articles in English." (Introduction to Sahidic Coptic, p. 5)
Since in the Coptic of John 1:1(c), ΝΕΥΝΟΥΤΕ ΠΕ Π?Α?Ε , we have a regular common noun construction, not an abstract noun construction, the objection of a difference in usage is irrelevant and misleading in this specific case.
Coptic grammar allows only two possible English translations Of Coptic John 1:1(c) according to Coptic grammarian Shisha HaLevy: (1) adjectival, or (2) indefinite. The definite translation, "the Word was God," cannot be obtained from the Coptic sentence.
Thus, the Coptic sentence can be rendered as "the Word was a god," as grammarian Bentley Layton does in the interlinear translation found on page 7 of his 2007 grammar book, Coptic in 20 Lessons, or as "the Word was divine/a divine being."
http://sahidicinsight.blogspot.com/2010/03/nominal-sentence-predicates-and-coptic.html
Of course, the underlying Greek text can also be translated to say "the Word was a god," as some theologians recognize:
"Now this [NWT] translation is normally laughed out of court by mainstream Christian commentators. And they are right to point out that “god” does not need to take a definite article if it is the predicate nominative. However, “and the Word was a god” is a perfectly legitimate translation of the Greek here."
http://thomstark.net/?p=1091
Or, the Greek can be translated to say "the Word was divine," as in Moffatt, An American Translation, and others.
Whether considering either the Greek or the Coptic text, there is no grammatical reason to keep "the Word was God" in English translations of John 1:1(c). If nothing else, the context of John 1:1, 2, where the Word is also said to be "with" God, makes such a translation of doubtful validity. If the Bible writer John meant to say that "the Word was God," there would have been no need to say twice in two verses that the Word was "with God."