From Alexander the Great onward Classical Greek became the most important language. At the time of the NT an easier "Koine" Greek was spoken and in which the NT is written. Before other ancient Greek manuscripts were discovered, it was thought that the NT was written in a special Holy Ghost language. The gospel of Matthew was most likely originally written in Aramaic then translated back into Greek. This would explain the similarities and differences it has with the other gospels. See the Website New Testament Greek for resources.

There are about 5,000 Greek manuscripts which contain part or all of the NT. There are three different kinds of manuscripts: (1) papyri, (2) uncials (written in large capital Greek letters), and (3) minuscules (written in small Greek letters). There are also three different text types: (1) Western, (2) Caesarean, and (3) Byzantine.