Both propositions seem pretty dubious, and whatever "modern Greek" might be it's not always clear to me that's what the transliterations in the Roman books are aiming at. Thanks though, the two previous threads seem to have covered a lot of ground.Italianate ecclesiastical Latin and modern Greek are the only legitimate pronunciations for Catholic liturgical use in English-speaking countries.
But, it does see a bit silly to intentionally mispronounce church Latin in a performance of a Mozart Mass because they did it in Salzburg in Mozart's day.
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