How can the New Testament be a Greek “translation”, when it was written in Greek originally?
There are folks who say "some" gospels were originally written in Hebrew......early church fathers among them. The gospel of Matthew in particular.
"For of one thing he took especial care, not to omit anything he had heard, and not to put anything fictitious into the statements. [This is what is related by Papias regarding Mark; but with regard to Matthew he has made the following statements]: Matthew put together the oracles [of the Lord] in the Hebrew language, and each one interpreted them as best he could. [The same person uses proofs from the First Epistle of John, and from the Epistle of Peter in like manner. And he also gives another story of a woman who was accused of many sins before the Lord, which is to be fount in the Gospel according to the Hebrews."
And........there are many other writings from early church history suggesting the same.