Actually, Jesus was bilingual, he could speak Hebrew, Greek, Aramaic, and Latin. When a Roman centurion spoke to Jesus, in which language to you think he spoke in? Why are all the oldest NT Gospels written in Greek? We have over 5, 300 Greek manuscripts of the NT. Under the influence of Alexander the Great and his succeeding generals, the Jews were hellenized, forced into Greek culture in part, as well as their language. So much so that most of the burial tombs among the Jews are inscribed in Greek.
"In the next article in the same issue of Biblical Archaeological Review, the author, Pieter W. Van Der Horst, points out that no less than 1,600 Jewish epitaphs -- funerary inscriptions -- are extant from ancient Palestine dating from 300 B.C. to 500 A.D. The geographical spread of these inscriptions reveal that Jews were living all over the world at that time, especially the Roman period. In other words, when Jesus' brother James said in Acts 15, "Moses has been preached in every city for generations past and is read in the synagogues on every sabbath" (v.21), he was simply stating the truth. Peter, in his first sermon, enumerates a list of the countries from which Jews came to worship on that first Pentecost of the newly formed Christian Church (Acts 2:9-11).
Van Der Horst goes on:
"One of the most surprising facts about these funerary inscriptions is that most of them are IN GREEK -- approximately 70 percent; about 12 percent are in Latin; and only 18 percent are in Hebrew or Aramaic.
"These figures are even more instructive if we break them down between Palestine and the Diaspora. Naturally in Palestine we would expect more Hebrew and Aramaic and less Greek. This is true, but not to any great extent. Even in Palestine approximately TWO-THIRDS of these inscriptions are in GREEK.
"APPARENTLY FOR A GREAT PART OF THE JEWISH POPULATION THE DAILY LANGUAGE WAS GREEK, EVEN IN PALESTINE. This is impressive testimony to the impact of Hellenistic culture on Jews in their mother country, to say nothing of the Diaspora.
"In Jerusalem itself about 40 PERCENT of the Jewish inscriptions from the first century period (before 70 C.E.) ARE IN GREEK. We may assume that most Jewish Jerusalemites who saw the inscriptions in situ were able to read them" ("Jewish Funerary Inscriptions -- Most Are in Greek," Pieter W. Van Der Horst, BAR, Sept.-Oct.1992, p.48)."
http://www.ntgreek.org/answers/nt_written_in_greek.htm
"Greek in Ancient Palestinian Judaism
But it also seems that Greek was known to ancient Jews. The influence of Greek culture in the first century is clear from the fact that the high priest in 37 A.D. had a strikingly Greek name--Theophilus. It is striking to me that he did not feel the need to change his name to a Semitic one--there was apparently no problem with this high priest being called Theophilus (Ant. 18.123).
Many sources could be cited here. Stanley Porter writes,
". . . Jesus would probably be best described as productively multilingual in Greek and Aramaic, and possibly Hebrew, though Aramaic would have been his first language and Greek and Hebrew being second or acquired languages. . . He may also have been passively multilingual in Latin, although if he had any knowledge of Latin at all it is likely that it was confined to recognition of a few common words. This depiction reflects the linguistic realities of the Mediterranean world of Roman times, including that of the eastern Mediterranean, and is supported by widespread and significant literary, epigraphic, and other evidence. As a result of the conquests of Alexander III ('the Great'), and the rule of the Hellenistic kings (the Diadochi and their successors), the Greco-Roman world was one in which Greek became the language of trade, commerce and communication among the now joined (if not always united) people groups. In other words, Greek was the lingua franca for the eastern Mediterranean world, displacing Aramaic. . . .
The arguments for the use of Greek in Palestine are based upon the role of Greek as the lingua franca of the Roman empire, the specific Hellenized linguistic and cultural character of lower Galilee surrounded by the cities of the Decapolis, and the linguistic fact that the New Testament has been transmitted in Greek from its earliest documents. There is also a range of incriptional evidence (e.g., Jewish funerary inscriptions), numerous Greek papyri, and significant literary evidence, including Jewish books being written in or translated into Greek in Palestine. From this range of evidence, the logical conclusion can be drawn that in fact a sizeable number of Jews in Palestine used Greek."--Stanley E. Porter, The Criteria for Authenticity in Historical-Jesus Research: Previous Discussion and New Proposals (London: T & T Clark, 2000), 134-5, 140-141."
http://www.thesacredpage.com/2010/01/did-jesus-speak-greek.html