The "Oxford" pronunciation is an English peculiarity, still used in some legal phrases such as "sine die" (pronounced "sigh-knee die" where "die" rhymes with "sigh"). It was, I believe, once used extensively in England, and made a contribution to the development of the Westminster system of government. You see, when the German-speaking George I became King of England, he ordered cabinet meetings (at which the King presided) to be held in Latin. Alas, he found he could no more understand the ministers' spoken Latin than their English - so he stopped attending Cabinet, and ordered one minister to bring him a written summary instead. Thus developed the important office of Prime Minister - or so I was once told!