I found myself wondering about the correct pronunciation of the Greek letter φ (phi). Somehow, I acquired the habit of saying "fee." But it turns out that mathematicians say "fi" as in "fly."
It seems that in Greek, the first pronunciation is correct. However, if we were to follow that route, we'd have to pronounce π as "pee," and that just feels wrong.
A more common question is about "data." See howjsay. I pronounce data like "date-uh." I have a memory of this being drummed into me in Latin class. Perhaps we should just "say it like the Romans did," but see the above for one problem with that approach. Anyone know an authoritative source?