On our music turn-in sheets, Kathy exhorted us to read our Latin pronunciation sheets over the summer. So I'm doing my part to oblige.
The six vowels in the Latin language are:
A, pronounced father (never fawn or fan), transliterated "ah"
E, pronounced fed (never fate), transliterated "eh"
I, pronounced feet (never fit), transliterated "ee"
O, pronounced fought (never foe), transliterated "aw"
U, pronounced food (never foot), transliterated "oo"
Y, pronounced feet (never fit), transliterated "ee"
AE or OE should be pronounced as E (“eh”) [but not "ay," no matter how the congregation sings it--P].
U when preceded by Q or NG and followed by another vowel is sung quickly and is part of the same syllable as the vowel which follows:
“qui, quae, quod, quam” (kwee, kweh [not "kway"--P], kwawd, kwahm)
“unda fluxit sanguine” (oon-dah floo-kseet sahn-gwee-neh)
Au/Eu/Ay are sung as dipthongs, with the greatest duration given to the first vowel and the second vowel introduced just prior to the following syllable or word:
“Laudate Dominum” (Lah-oodah-teh Daw-mee-noom)
“Victimae paschali laudes” (Veek-tee-meh pah-skah-lee lah-oodes)