[narag]

Voseo is only used in Argentina, not sure if also in Uruguay. It's very localized, but still accepted and documented. Rest of speakers understand it no problem, it's very easy to get used to it.

This link to the Spanish Real Academia web shows a verb conjugation (scroll down):

https://dle.rae.es/hablar?m=form

It includes the usted,vos forms.

[lcall]

I know "vos" (which I think voseo means, from this discussion?) is also used in Guatemala, and someone else here mentioned it as used in Paraguay. I read years ago that such things originated based on in which century and from what part of Spain someone migrated.

[narag]

Vos is an archaic pronoun that was used to address the nobility. Like usted it was associated with a different verbal form, in this case the plural. You address a noble as if he was more than one person. I guess that's hard to appreciate in English that doesn't make a differece even in the pronoun: you for one you and you for multiple yous.

Argentinian Voseo is using the pronoun but not the majestic plural. Instead they create a brand new form, altering the accent. I had no idea that it was so extended outside Argentina. That surprises me because I know people from many of the relevant countries and had not heard any of them using it, except Argentinians.

[lcall]

Interesting; thanks. Actually I don't know how heavily "vos" is used in Guatemala. I know it is used extensively (I heard it occasionally: "mir'a vos", like "look, dude"), but I got the vague impression it might be mostly youths being chummy with each other, and/or could be considered less-educated, but I'm really not sure at all. Other missionaries and I always used Usted regardless of who we were talking with. I did hear that "tu" was only for boys trying to sound romantic to their girlfriend, imitating television.

[ChainOfFools]

English once did have a 2p distinction - 'you' was formerly the plural form, singular was marked by the now archaic 'thou.' Thou disappeared during the 17th and 18th centuries and "you" + context assumed the duties of both pronouns.