Yes, that's just it. The KJV is not a translation of the Vulgate, though it refers to the Vulgate, particularly in the New Testament, the RSV is most certainly not — it explicitly translates from the Hebrew and doesn't even give the Greek text of certain passages in th appendix — and the Douay-Rheims edition is wonderful but I can sort of see why people won't use it, on literary grounds as much as the fact that it's very clearly trad. (This is not a point in favor of the KJV's perceived literary merit as much as it is to say that the D-R has a long editorial history.)

Everything you say is true, but I fail to see how any of these versions could not be used in theory. There are good reasons to use either of these translations. Not to mention the fact they have already been used in plainsong, at least as far as the KJV and DR (to a lesser extent) are concerned.
If, however, these versions could not be used, perhaps the texts could be directly translated from the Latin. This has already been done if I am not mistaken.

I'm not sure why how the Latin could be kept in a meaningful way once the vernacular is introduced, so no, the problem is not resolved. It is simply dismissed.

Quite simply because this is the situation we see today: there are a lot of people around the planed who love Latin in the Sacred Liturgy, and would want to keep it even if the vernacular is authorized. This is not a problem.
Ceteris partibus, in the 1950's, some Russian Orthodox churches in France gradually adopted French into their Liturgy, for genuine pastoral reasons. Yet, to this day, the cathedrals and greater churches in France have kept Church Slavonic almost exclusively. That's not to say there weren't any tensions, but on the whole, those who wanted to keep Slavonic kept it, those who wished to have French had it.

And the RSV-2CE does have the full Catholic canon, hence the CE = Catholic Edition.

It doesn't, unless I'm missing something. The translation of certain books does not match the Vulgate or the Septuagint as the Hebrew was the point of departure; this is specifically the case for Sirach. I also know of no modern translation that includes the Johannine comma, which, like it or not, is a part of the liturgy.

What do you mean by 'in a meaningful way'? I would be delighted with a Mass completely in Latin except for the readings and orations and sermon, (and any other presidential remarks to the congregation in line with Trent 22:VIII). Propers sung by the schola from the Graduale, Ordinary by the congregation and schola from the Kyriale, Common as in the Toni Communes by priest and people.

Where this is done everywhere, like is the norm, or at least isn't made complicated with all sorts of bespoke options, which is exactly what you have proposed, while the rest of the people use the vernacular for everything but an occasional chanted Mass ordinary (VIII and/or XVIII). Also, on the translation bit: why would you translate the orations if you've kept everything else that belongs to the priest alone in Latin? They're one of the most difficult parts of the liturgy to translate.

Insofar as translations are concerned, there are not only compromises, but crazy innovations. The French, Spanish, and Italians can't figure out the Lord's Prayer, and the Italians the Gloria; I don't trust any of the powers that be with the rest of the Mass, and the ICEL translation still leaves something to be desired even if the pre-2011 translation was horrible. The Ordinariate's is a model, but nothing more — the Cranmerian collects say more than the Latin originals, for example, and I wouldn't want to impose them on anyone else, particularly with the absolute howler which is Sexagesima; the explicit reference to Saint Paul should have been restored. It was not.

As to the Orthodox, nevertheless, genuine vernacular liturgy is a far more recent phenomenon than most partisans of the vernacular admit, and there is absolutely no hostility to using the original texts. You simply can't be ordained without a knowledge of one or more ancient languages (Greek, Church Slavonic) and often the vernacular of the church to which you belong (notably Arabic for Melkites and others in the Antiochian tradition). Now, you might have a pretty bad knowledge in practice, once you're removed in time from your studies, but the generational hatred of Latin has no real equivalent in the East.

Hawkins, I keep seeing this quote from Trent pop up in this forum. Surely it is not meant to suggest that the priest halt Mass in order to explain what he's doing, or that some aspects of the Mass be in the vernacular, but rather that, while preaching, he explain various liturgical actions or prayers which are part of the celebration of Mass, no?

while preaching, he explain various liturgical actions or prayers which are part of the celebration of Mass, no?

On top of this Christine Mohrmann's Liturgical Latin is essential reading, and one can easily find any number of master's and doctoral theses from the same period just before and after the council that talk about the orations of the classical Roman liturgy.

But in any case, in reality, this does mean abandoning Latin, and why can't pastors of souls just do their jobs and instruct the faithful on the meaning of the liturgical texts and the sacred rites?

trentonjconn - I expect you are correct, I have no certainty what they had in mind. In French dioceses it seems to have been assimilated to the prône. And the use of the prône once a month continued to be enjoined† in Quebec until the eve of VII. About three years ago on Canticum Salomonis there was an example of the full form (the Great Prone), which would only have been deployed a couple of times a year, but I have not yet located the post.

In its more developed form the Prône included a translation or paraphrase of the Gospel reading, sometimes with an explanation, a catechetical instruction based on the creed, Lord's Prayer, or Commandments, bidding prayers, as well as notification of the banns of marriage and other announcements. ¡ Wikipedia !

"On Sundays and feast days, after the sermon preached during the solemn Mass, the pastor will, in accordance with the advice of the Apostle, have the people pray for all the different needs, to pray for the king, … for peace, for the sick of the parish, for the dead; and for each of these intentions each one will say privately the Lord's Prayer and the priest will say the appropriate orations." [M. F. Grancolas, Les Anciennes liturgies (Paris 1697) 1:525–526]

† The requirement still stood in diocesan instructions on the conduct of a parish, but the last printing of the prône was in in 1919, copies ran out after about twenty years, and in the mid50s there were "no plans to reprint it"

[Added] Here , found something like it.

@Jackson

( 2 ) - I have never studied this matter but have heard it mostly second hand) that the Authorised Version (KJV) contains here are there translations which are said not to be compatible with Catholic teaching. Would a greater authority on this than I care comment or elaborate?

I am no greater authority, far from it, but it seems to me most of the KJV is compatible with Catholic teachings. There may be one or two verses which might be controversial ("Hail Mary, who was highly favored"), but even they can be interpreted in a Catholic light.
Are you familiar with the "KJ Bible for Catholics", which was published a few months ago?

As a side note, I don't really see the problem with two (or more) languages inside the same liturgy. But this might be a matter of taste rather than anything else.

Sad to say, I think some remember just how bad American Catholicism was before Vatican II and don't want it back. Now, whether those memories are correct or distorted by time and distance could be another matter.

MJO, your suggestion on one-language Masses makes a certain amount of aesthetical sense. However, in the overwhelming majority of OF parishes, this would practically eliminate anything Latin from ever being sung, as most OF priests would be absolutely unwilling to say Mass in Latin. Would it be nice to have, say, a 9am sung Mass with chanted English ordinaries, propers orations, and hymns followed by perhaps an 11am of the same in Latin? Ideally, sure. But that's really a fantasy (I do love a good liturgical fantasy though). If we are to preserve and foster Latin as the council calls for, there is really no way around having a mix-and-match of languages during Mass.

That said, I do agree that all of the ordinaries in a particular Mass ought to be the same language (with the Kyrie being the obvious exception), and I feel the same way about the propers.

There is a sense in which yes, the Kyrie is composed of Greek words, but it's made of Greek words that are borrowed into Latin.

indeed I would venture that it's relatively rare that a given setting of the ordinary is so extraordinary that it should be an all or nothing thing.

If you do this and regularly break up the chant ordinaries with one or two parts in the vernacular, you will never get people over their hang-ups, you will disappoint your supporters, and people will never learn an entire ordinary without some substantial effort. It's very frustrating, and it's not quite predictable either, in my experience, when it comes to special occasions.

They are used in Latin without alteration, similar to how hors d'oeuvre is used in English without alteration. For all practical purposes, hors d'oeuvre is an English expression even though it's French.

It seems strained to suggest that the Greek words in the Good Friday liturgy are not simply meant as Greek. The Triduum liturgy has elements from very early sources, so why not just accept that it quotes the Greek Trisagion ("Holy God, Holy Mighty, Holy Immortal...") and also sings a Latin translation of it?

Yeah, tomjaw made my point for me: the treatment of the text is based on Latin, not Greek. The Hebrew letters are read in the Lamentations of Tenebrae as Latin words, taking absolutely no account of the Hebrew pronunciation.

Anyway, the reason that I bring this up is not entirely pedantic: I've been down the rabbit hole a number of times where people say "but the Kyrie is in Greek, not Latin," as if it's some kind of excuse for the vernacular; they mistakenly think that it's a remnant of the ancient Roman liturgy, rather than something brought back from Constantinople by Saint Gregory the Great, which is an argument for bringing back vernacular liturgy, as we once had it in the West. Pointing this out and that the Latin liturgy just absorbed 'Kyrie eleison" makes this argument disappear, and your interlocutor will probably leave in a huff.

I am trying to move in the opposite direction from vernacular only towards an enthusiasm for what the Church (VII + popes) has asked us to do, which involves vernacular and Latin, particularly sung Latin. And I use "but the Kyrie is in Greek, not Latin," to reduce the suspicion that I want Latin only, though "well Alleluia and Amen are Hebrew" is more likely to be accepted.