Time was when the dear old Catholic Truth Society did a nice, uniform series of English translations of Papal Encyclicals. Page 2 always gave the AAS reference and the name of the translator. Fr Winstone ... Canon Smith ... one almost got to know them. At some point, this stopped. Instead, we got the sinister little phrase Translation by the Vatican Polyglot Press.
After a few years of this, a particular and most objectionable mistranslation became standard. The convention by which the Sovereign Pontiff referred to himself as "We" was abandoned; instead, he became "I". I must make clear that this did not represent a change in the Latin originals. In them, the Pontiff remained "Nos".
Does this matter? After all, a chap or chappess nowadays does not commonly call himself or herself "We" unless they happen to be Lady Thatcher. "We" sounds old fashioned. A translation should be in modern English. Yes?
It matters a very great deal. "We" implies that the speaker or writer is not an individual expressing personal views. "We" means that the speaker is, if not a corporate being, then at least a formal being within a formal corporate structure. "We" means that the pope is acting as Pope, as the Bishop of Rome, as the Church's foremost Teacher; the text concerned has, in down-to-earth terms, been across the desks of the relevant Roman Dicasteries and been checked for error; put more formally, it expresses the settled and authentic Magisterium of the Church throughout the ages and of the world-wide Episcopate of the present. It does not come to us as the bright ideas of a clever chap; as S John Henry reminded us, originality and brilliance are not historically the charism of the venerable Roman Church.
In the Bull defining the Dogma of the Bodily Assumption of our Lady, we have, at the end, the signature of the Pope, the Bishop of Rome. But there follow the signatures of a majority of the Cardinal Bishops, Cardinal Presbyters, and Cardinal Deacons ... the clerus Romanus. This appropriately expresses the fact that the Pope did not make that teaching as an individual; he made it out of his unique position upon his cathedra within the corporate structure of the Church of Rome.
I suspect that "We" goes back very far indeed. It is certainly a convention found in the homilies of S Leo and S Gregory. But more: the Bishop of Rome is not the Church's only Teacher; every bishop has a Magisterial charism. And if you look back into the old Pontificals ... for example, at the Rites of Ordination ... you will find that the Pontiff is "We". The Anglican rites of Ordination continued this convention (except, strangely, in the Interrogatio of a consecrandus).
If a polyglot Roman document fails to make clear which version of it is authentic, it thereby gravely impairs its authority. I also believe that a Papal document in which the Pope is "I" rather than "We" has a considerable Magisterial deficit.