Either has two different pronunciations in modern English. The pronunciation IPA: /"i;D@/ prevails in American English, and is the pronunciation of the majority of English speakers. The pronunciation /"aIð@/ is associated with British English and Canadian English, but it is not universal in either place or in Australian English and other dialects that take their lead from British English. It is also found in the U.S., especially in New England, although many Americans will regard it as an affectation.
An Ira Gershwin song, Let's Call the Whole Thing Off, opens with the words "You say /"i;D@/ and I say /"aIð@/", and concerns a couple who lament the difficulties in their relationship by pronunciation differences (and the different social backgrounds which they imply). These differences between the two lovers could be the reason to call off the relationship. But they can't stand the thought of being apart so the singer will compromise for love.
Click on the image below to see the lyrics in full size: