May I speak as a specialist who has devoted considerable time and
energy to this issue?
Jim Oxford has given exactly the right advice--namely, to read the
extremely well-balanced, and thoroughly fair, discussion of the issue in JP
Meier's _Rethinking the Historical Jesus_, Vol. 1, pp. 255-268. (Jim calls
this "a terse discusson", which is probably true--it IS terse, but not brief
or simplified.) In addition to these 13 pages, there are 76 footnotes,
citing or referring to the evidence and arguments for all sides of the
question.
Regardless of where you come down (and it certainly can't be
settled on this List!), this material ought to be in your grasp, and
digested before stating an opinion. Meier makes it clear how difficult the
problem is; but he DOES come down. His conclusion:
". . . the most probable opinion, viz., that Jesus regularly and
perhaps exclusively taught in Aramaic, his Greek being of a practical,
business type, and perhaps rudimentary to boot. In a quadrilingual country,
Jesus may indeed have been a trilingual Jew; but he was probably not a
trilingual teacher." (p. 268)
For those who do not know Meier or his work, he is Professor of NT
at Catholic University, and has been President of CBA, and general editor of
CBQ.
Many thanks to Jim Oxford for reminding us of this resource.
Edward Hobbs