Aramaic is a Semitic language that is closely related to Hebrew. It had its origin among the Arameans of northern Syria dating back to the ninth century BCE. (These were believed to have been Abraham’s ancestors.) When the Assyrians conquered the Arameans, various scribes were instrumental in making Aramaic the universal language for the area. This lasted for hundreds of years -- until roughly the 4th century. Scholars liken it to the position held by English in today’s world. Manuscripts from this period would have been written in Aramaic. By the time the Israelites returned from Babylon, most had made the switch from Hebrew to Aramaic in their spoken language. It is noteworthy that several OT books were thought to have been originally written in Aramaic, including Daniel and Ezra. Aramaic, then, was the dominant language for Jewish cultic life.
This is supported by the findings of the Dead Sea Scrolls, which contained many Aramaic documents. Since Aramaic was the language of choice (and Hebrew was dying out as a language), it was used during the worship service. Since the sacred texts were still written in Hebrew, they needed to be translated into Aramaic so they could be read during the synagogue services. These translations were called Targums (a “translation” or “paraphrase”) and were written from about 250 BCE-300 CE.
Also about this time, a group of Greek-speaking Jews from Alexandria began clamoring for the Hebrew Scriptures to be translated into Greek. Legend has it that six members from each tribe were sent to Alexandria with a copy of the Torah. They were able to translate the Hebrew into Greek within 72 days (285-246 BCE). This is historically doubtful, but it led to designating the translation as the “Septuagint,” or LXX in Latin numbers. LXX, of course, in Latin is 70, a rounding down of 72.
There is no doubt that Jesus and his disciples spoke a regional form of Aramaic. This is confirmed by noting the several Aramaic words sprinkled throughout the NT texts. The language of choice for that area, however, was universally Greek. Obviously, the gospel stories had a long oral tradition, but when the need arose for them to be written down, most scholars agree that they were written in koine Greek, the common language of that day. There is no doubt that the style and vocabulary of the NT Greek had been influenced by the area’s Hebrew and Aramaic backgrounds. Yet, the study of precisely how, when, and where this occurred is only in its infancy.