One must remember that Copeman is an Englishman and "O as in 'for'" has a different pronunciation than in American....there is no pronounced R at the end of that word, but the R also takes out the diphthong (that you would get in "go") and opens the vowel.  Therefore, O in Italianate Latin is an open O as in "caught" or "dog".  It would be represented in IPA as a backwards c symbol.  The ancient Romans also distinguished between open and closed vowels for each vowel which are referred to as "short" or "long".  The Italianate pronunciation of Latin condenses the vowels into an easier system.  I'm doing a thesis and recital on the various regional pronunciations of Ecclesiastical Latin in Los Angeles area in CA on 11/7/09.  We will be singing works in Italian, Germanic, English, and French Latins.

When we say "Roman" usage, this is confusing b/c are we talking about Classical Rome/Classical Latin or Church Latin?  It is better to say "Classical Latin" for the pronunciation of ancient/classical Rome and "Italianate Latin" for the Latin used by most choirs today.  Although Classical Latin belongs to the Roman empire, it was really Vulgar Latin which was spoken by the people which pronunciation is not really known; and the Classical (whose pronunciation we do know) was probably more of a literary than spoken language which the upper class forged (with heavy borrowing from Classical Greek syntax and rules, etc.). 

"Ecclesiastical Latin" refers to a set of vocabulary developed for used by the Church - it does NOT refer to pronunciation.  In fact, Ecclesiastical Latin had various pronunciations depending on region of the empire and century.  Furthermore, when those conquered by Rome (Celts/Gallics, French, etc.) were imposed the Vulgar Latin language, they definitely pronounced it according to their own language rules and pronunciations.  Now, we don't know what the Vulgar sounded like, but we do know how the regional pronunciations sounded.  So to say that the Italianate is the only or proper way is wrong since it also is an evolution of the Vulgar.

 

In 1903, Pope St. Pius X mandated that all Catholics use the Italianate pronunciation.  His reasoning is that it was closest to the Classical (again, which was used for literary rather than speaking purposes...remember that the Mass texts and Bible were translated into/written in Vulgar Latin); and also in order to keep the Classical (Vulgar?) word stress which Gregorian Chant is based on (in French Latin, the last syllable is emphasized - not the ante/penultimate).  This caught on in the Anglican Church soon and in the choral world after many years (the bishops in Germany only threw in the towel in 1972).

 

Any more questions, just ask me...!