Koine Greek is different from Classical Greek. It was the common multi-regional form of Greek spoken and written during Hellenistic and Roman antiquity. Though it was really Greek it retained many words, phrases, grammatical structures, and patterns of thought characteristic of the Hebrew language. The New Testament was written in this language. 

      Recently, a number of authorities have suggested that the first few books of Genesis may have originally been written in a proto-Hebrew text. This was a language not yet fully developed as Hebrew

Translations

     The very first translation of the Hebrew Bible was into Greek. This translation is known as the Septuagint, a name that derives from a legend that seventy separate translators all produced identical texts; this legend was created to promote the authority of this translation. In fact, the development of the Septuagint was a gradual process: it began some time in the 3rd or 2nd century BC, when the first portion of the Hebrew Bible, the Torah, was translated into Koine Greek. Over the next century, other books were translated as well. The Septuagint was widely used by Greek-speaking Jews. It differs somewhat in content from the later standardised Hebrew Bible, known as the Masoretic Text.

     Later, for Christians, the Septuagint became the accepted text of the Old Testament in the Catholic Church, and the basis of its canon. The Latin Vulgate by Jerome was based upon the Hebrew for those books of the Bible preserved in the Jewish canon (as reflected in the Masoretic Text), and on the Greek text for the rest. Other ancient Jewish translations, such as the Aramaic Targums, conform closely to the Masoretic Text, and all medieval and modern Jewish translations are based upon the same. Christian translations also tend to be based upon the Hebrew, though some denominations prefer the Septuagint. Bible translations incorporating modern textual criticism usually begin with the Masoretic Text, but also take into account possible variants from all available ancient versios.

                  Languages of the deuterocanonical books

     The books located between the Old and New Testaments have a different status according to various Jewish and Christian denominations, with some considering them canonical, others apocryphal. These books, mostly written between 300 BC  and 300 AD, were written in various times, places, contexts and languages by various authors for various reasons. Scholars continue to debate as to which languages each of the deuterocanonicals was originally written. Many of the oldest surviving texts are in Koine Greek, but show features of Semitic languages such as Hebrew, Aramaic or Syriac, leading some scholars to argue that the original text, even though now lost, may have been written in a Semitic language rather than Greek. In other cases, the Greek seems more fluent and may be considered original.  2 Esdras, probably a mix of Hebrew, Latin and Greek origins.