Why is the diphong "ae" pronounced as "ae" as opposed to "ai"?
Side question: we were taught at (Ukrainian) medscool to read "ae" as "e". Here it's pronounced "ai". Were all the teacher of our Latin language department wrong about it?
at medschool you were probably taught to pronounce it as ee because that's the Greek pronunciation and most medical terms have Greek origins. The pronunciation of ae as "eye" is the classical Latin pronunciation. The classical pronunciation tries to copy how the Romans would have spoken during the time of people like Cicero, Julius Caesar and Augustus.
As well as having the classical pronunciation, Latin also has an ecclesiastical pronunciation which is how Latin has been pronounced in the Catholic Church for the past few hundred years. This pronunciation is closer to modern Italian, pronouncing c as "ch" and ae as "ay"
Well, I must have represented the sound wrong because we weren't taught to pronounce "ae" as "ee" (the sound [i]) but rather as the sound [ɛ] (as if there was no diphthong at all and the word was written as "olive", for example).
So that's even a third variant of pronunciation ([ai], [i] and [e]) that was either made up by our department or was used at some point in the past.
It would be interesting to know how the pronunciation changed over time but I guess that is some advanced level stuff