Regarding Vos
In those Latin American countries where they use vos, they use it instead of t?. They do not use vos they way it was traditionally employed in the past, for example, the correct way is to say: Vos sois, Vos teneis, etc. The same way it is still used with vosotros. This Vos used to be equivalent to the French Vous, but while the latter is still used to formally address someone, in Spanish the former is no longer used this way, except in plays. Vosotros was retained in Spain only, as the second person plural. The rest of the Spanish speaking world uses ustedes instead, although in truth, it is conjugated like the third person plural, in other words, like ellos.
Ustedes son, Ustedes saben
Ellos son, ellos saben
The reason for this is that usted is a contraction of two words: Vuestra Merced. Something like Your Honor, or Your whatever: So in English one would say to a judge: Is your honor aware of.... or Does your higheness know.. always using the third person, even though you are addressing someone in front of you. So it is in Spanish when you say: Usted sabe... It is conjugated the same way as when you say El sabe.
That is the reason why you most often see
Nosotros
Vosotros
ellos
and not
Nosotros
Ustedes
ellos
Although in reality, this is the way it is actually used by almost everyone, including people in the Canary Islands and many in Andalucia and everyone in the Americas. Only in the rest of Spain they use vosotros as the familiar plural for the second person. The rest use ustedes both as the familiar and the formal plural.
