Most of the Hellenistic Jews spoke and read Greek rather than Hebrew in the 1st century.
The modern Jewish texts are corruptions. The Dead Sea Scrolls prove that the older Hebrew was far closer to the Septuagint than the Massoretic texts used by Jews and Protestants.
I realize the wikipedia is a popular source for information, however much of it is biased towards those who post it. From "Understanding the difficult words of Jesus" by David Biven...
Since the discovery of the Dead Sea Scrolls, however, the leading proponents of the Aramaic theory have gradually begun to modify their views. Matthew Black, for instance, in the 3rd edition of his influential book, 'An Aramaic Approach to the Gospels and Acts' remarks:
The Qumran discoveries have also shed fresh light on the problem. M.Wilcox writes: "With regard to the matter of language, we ought to note that the discovery of the Dead Sea Scrolls has now placed at our disposal information of a highly interesting and relevant nature.... The nonbiblical texts show us a free, living language, and attest the fact that in New Testament times, and for some consideable time previously, Hebrew was not confined to Rabbinical circles by any means, but appeared as a normal vehicle of expression.
If this is a correct estimate of the Qumran evidence, where Hebrew certainly vastly dominated over Aramaic, then it may be held to confirm the view identified with the name of Professor Segal that Hebrew was actually a spoken vernacular in Judaea in the time of Christ" (Black 1967:47)
Greek Theory: ...it remains an important fact that the poor Greek of the Synoptic Gospels id found basically only in literary works that are translations from Semitic originals, such as the Septuagint...many Gospel expressions are not just poor Greek, but actually meaningless Greek....example Mt 6:22-23 reads "the lamp of the body is the eye. If your eye is good, your whole body is full of light; but if you eye is bad your whole body is full of darkness...". the expressions "good eye" and "Bad eye" are common Hebrew idioms for "generous" and "Miserly". Greek as no such idioms, and in Greek this statement of Jesus is meaningless, just as it is in English....Are we claiming that the Synoptic Gospels were not originally written on Greek? To this we must answer "yes" and "no". The Synoptic Gospels as we have them today were originally written in Greek; however the text from which they descended was originally translated from a Hebrew archetype...it is the undertext of our canonical Gospels that reveals the Hebrew origin... Our canonical Gospels are based on Greek texts derived from Greek translation of the original Hebrew story of Jesus...It is most unfortunate that our Bible colleges and seminaries focus their attention on Greek and Hellenistic theology, and fail, by and large, to equip their students with the proper tools that would allow them to do serious bible exegesis...The evidence for Aramaic or Greek origins of the Synoptic Gospels simply will not stand up under critical analysis. There is far more substantial evidence indicating a Hebrew origin of the Synoptic Gospels."