JerryZ:
So I would venture, that mass was being offered in Rome both in Greek, Latin and possibly Aramaic as early as the 1st Century AD.
Which wouldn’t surprise me given that things were so variable in the first centuries of the Church. But the official liturgical and ecclesiastical language of the Western Church was Greek up until Pope Damasus in the 4th century (although Pope Victor began initiating changes in the 2nd century).
The vast majority of Western Church writers wrote near exclusively in Greek: Hippolytus, Clement, Hermas, Caius, etc. I think our first extant Western ecclesiastic who wrote predominantly in Latin was Pope Victor.