Product of Latin American school. 
Yea, we were told about the vosotros form. Also with comments like “just for completeness, you would not normally use this around here”. We were also told of some sort of dialect that uses the vos with the tú conjugation.
BTW, I still see judges being referred as Su excelencia (use of usted, not vos). 
Re: Mass – the individual national Episcopal Conferences have quite a bit of leeway over details within the Ordinary of the Vernacular Mass. So in many parts of the Spanish-speaking world the speech used in Mass (specially in the regular non-high-solemnity services) has de-formalized over the last 30 years. Thus you may hear “la Paz esté con ustedes” instead of “la Paz esté con vosotros”
Re: Second Person Plural. Originally, Ustedes was indeed the second person formal; however, as the language evolved, it became the more common form, and “vosotros” began taking on an aura of formalism/archaism. Around here, it depends on what school you’re in, but since “ustedes” conjugates with the 3rd person form, Middle-School Spanish teachers are quite fond of “Vosotros” as an instrument of torture to add another verb tense form (e.g. "Please provide the example of the second person plural pluperfect subjunctive, first conjugation [“vosotros hubieseis amado”])
Again concerning Mass:
From: Academia Mexicana
Consulta : Se han enviado a Roma, para su aprobación, las versiones de las lecturas bíblicas que se utilizan en las celebraciones litúrgicas hechas para México. En estas traducciones se ha utilizado el ustedes y sus correspondientes formas verbales, en vez del vosotros y las formas que a este pronombre corresponden Para ser aprobadas se nos solicita un documento de la Academia Mexicana en el que conste que el uso de ustedes es correcto y habitual en México (obispo Efrén Ramos Salazar, presidente de la Comisión Episcopal de Pastoral Litúrgica).ustedes
**Respuesta: ** En efecto, en México no usamos el vosotros. Más aún, muchas personas no lo entienden, al igual que la forma verbal correspondiente. Por ello lo sensato, en las versiones de las lecturas bíblicas utilizadas en las celebraciones litúrgicas, es reemplazar el pronombre vosotros y sus respectivas formas verbales, por el ustedes, pues éste es el correcto y habitual en México (Manuel Alcalá, secretario perpetuo).
Originally posted by Estilicon
Similarly, I found a Jack Chick tract in Spanish. Where the English equivalent uses “Ye Must Be Born Again,” the Spanish uses Os es necesario nacer otra vez–using the oblique second-person pronoun os.
I found that when reading “The Godfather” in Spanish, it used os a lot. I just imagined it was common in Spain, since there was other Spanish-Spanish usage (but the same grammar that everyone uses).
I would consider the virtual complete replacement of one pronoun by another, together with its corresponding verb forms, to indeed be a grammatical difference between Latin American and Iberian Spanish. It doesn’t matter if the other form survives in some very limited contexts, or if it is used grammatically in those contexts. This a rather more basic change than the simple use of differenct vocabularies (“truck” vs “lorry”) in English, or differences in spelling (“color” vs. “colour.”)
Similarly, the loss of the “thee/thou” forms in English over the past few centuries is a grammatical change, even though these forms survive in limited contexts (the Bible, Shakespearean plays, and among Quakers). These forms may still be conjugated correctly when they occur (although I suspect that many people wouldn’t know how to do it), but the fact that they are never used in common speech constitutes a shift in grammar.
By your definition any change in language seems to me to be a change in “usage.”
Whatever the case, I think that Spanish shows greater divergence between its European and American forms than English does. This is understandable, since American Spanish began diverging more than a century earlier, and has also been subdivided into more political units that developed in isolation from one another and in some cases from the mother country.
Well, I, a reasonable well-educated native speaker will disagree with you, if I may. The difference between ‘European’ Spanish and Latin American Spanish is not that much when you compare how it is spoken in many countries in America. To my ears Uruguayan and Argentinian Spanish sound more ‘foreign’ than that of Andalusians. Caribbean Spanish is somewhat archaic, more so in rural Dominican Rep., but I have yet to find somebody whose Spanish I can’t understand, I have never seen a movie in Spanish with subtitles in Spanish (something I’ve seen many times in English).
Apparently my education is worth a damn when it comes to spelling.
I agree with you that Latin American Spanish is more divergent between the different forms spoken within the hemisphere than American (that is, the forms spoken throughout the hemisphere) English is. However, Latin American Spanish in general is also more divergent from Andulusian Spanish (its immediate predecessor) than American English is from the British dialects from which it directly descended (specifically in the case of the ustedes/vosotros distinction). There may be more divergence within Great Britain between the various dialects of English, such as Scots (sometimes even considered a separate language), than there is within Spain for Spanish dialects. And it’s these British dialects of English, not dialects of American English, for which you might need subtitles.
(One might also need subtitles for the Jamaican English Creole, but there are some American Spanish Creoles such as Palenquero that are even more difficult for a Spanish speaker to understand.)
Actually, the quote is properly rendered as “Veni, Vidi, Vici”, and would thus be pronounced “Vain-y, veed-y, veech-y” (as my dad learned it at Cleveland’s Benedictine High School in the 1950’s), or “Wain-y, Weed-y, Wee-ky” (as Dr. Stephens, a political science professor I had in college, said in the way he learned the language under a “prominent Latin scholar” at the University of Chicago).
Except that “vuestra/s” is a possesive pronoun = “su/s.” It has nothing to do with “vosotros” = “ustedes” wich are second person personal pronouns.
i.e.
Vosotros, los Argentinos, sois los habitantes Hispanos mas cercanos al Cono Sur y vuestras vacas producen la mejor carne.
Ustedes, los Argentinos, son los habitantes Hispanos mas cercanos al Cono Sur y sus vacas producen la mejor carne.
Guess which of the two is considered a more formal way of address in Spain?
Just thought up something here that may be confusing all of us – are we equating formal with polite forms? To me, usted and ustedes are “formal”/polite, in that you speak to your elders or the queen in a formal fashion. Granted ustedes has displaced vosotros in Latin America, so it’s used in general, not just for formality and politeness. So, someone way up above said that if they were to hear vosotros used, it would be kind of stodgy and formal.
Dunno about using usted in general terms. Tú is the familiar, general one.
I said ustedes.
Heh, sorry for that, too early too notice.
Is this a regional variation? I was recently on the webpage of a guy who’s Venezuelan, who offers the site in “English” or “Castellano,” and I was wondering.