Latin: R. Gloria tibi Domine!
Old text = People: Glory to you, Lord.
New translation = People: Glory to you, O Lord.
The Latin is clearly vocative. Some languages has vocative others don’t. I may be wrong, but my understanding is that the English has no declinations of the noun at all (except may be the possessive 's and plural s), so it does not has vocative either.
May question is:
- when the English feels necessary to represent the vocative by nominative and the O prefix , so why not like at Shakespeare: Et tu Brute = And thou, Brutus
As for curiosity the Hungarian has no ending for vocative, but in the Bible and Ecclesiastical text the vocative is represented by adding an ending with the meaning of my Lord or our Lord, if there is no adjetcive before the person, so almost always the equivalent of Almighty God, instead of our/my Almighty God.