I don't want the way people talk to be used in mass. With Italian, people weren't talking in Latin, right? Therefore, Latin couldn't be dragged down by slang and other lazy talk. When people pray in lazy language, they are not going to respect the Faith. If the Masses at least used classic (like, "Oh, that I might see the face of God and be forthwith slain by his Holy Face") ways of speaking English, then maybe. The Ecclesia Dei Commission has missals that have English--Latin and even Spanish---Latin. You know, though, as prosperous as we are in the West, as a whole, we could have been taught English as a second language.
I think Jews still learn how to at least pronounce Hebrew before their Bar/Bat Mitzvah (sp?). I think Muslims learn Arabic, if possible. Why aren't Roman Catholics learning Latin along with English, Byzantine Catholics learning their liturgical Greek, etc.? Catholicism is a monarchy with God (Christ being the identified as, amongst the 3, the king of mankind) as king (the Pope as a prime minister, and a culture in and of itself.

Other rites are like how Canada has Quebec and probably Spanish areas. We let people speak Creole as long as they also know English. English is still their and our (as Americans, though there's Australia and New Zealand too) business language. Latin is the primary Catholic liturgical language, but it's ok to honor the language of your hometown as well. We should all know Latin, as well as any other language that's part of a different rite, lest we slip into a pseudo-version oriented more to the secular culture and its modernism. People will make a great effort to learn secular languages, but not their faith's. Words of different languages can carry special meanings that will take the society down with it if forgotten by them into modernism hell. Language, borders culture. Whatever you think of Michael Savage, those are important for Catholicism.

I don't remember what Jansenism was, but in a time of rebellion, people will get puffed up with Pride. It's only a step between reinterpreting the Bible to accomodate your personal feelings (scrupulosity leading to Pride in Luther) to ditching the Bible and rewriting charity based on your own feelings about life. The Church understood this rightly, I believe. Still, there were, I understand, vernacular versions before Martin Luther came along. If not for Luther, the Church my have been more open to vernacular Bibles. Well, St. Francis wanted that, but that, too, was a time of declining morals and people only needed a reason for lazy and/or idealistic, but Proud, minds for a breakaway.

Now English is becoming the language most familiar to the whole world; not Latin and it will match the last piece in the socialism puzzle in the Americas. Next, Asia and then, if we get there, an unholy trinity with a Tower of Babel rebuilt, though not in the same way or design. Unless China leads the way in consolidation via popular fiat of those in other Asian lands (though not directly), their time may come--but I digress.

Interesting points. The first bit there about praying in 'lazy language', that's pretty thought-provoking; I've never thought about it like that. I don't think it's too much to ask for people to learn at least a basic level of ecclesiastical Latin, at least enough to be able to understand the mass if it were in Latin. I also think your point of if not using Latin, at least using what one might call "Elevated English" so that the sacred and profane stay separate.

Good food for thought...

I'm a second year latin student

I hope to teach it to my kids as well.

Personally I prefer the vernacular, but I think it is a good thing to do some of the liturgy in Old Church Slavonic.