According to the Diccionario panhispánico de dudas, voseo means to use the pronominal “vos” form when talking to somebody. Though this has been shown in a previous post to be a phenomenon of the River Plate region, in Costa Rica, as in a great number of countries in the Americas, the pronoun “vos” is adopted when referring to the second person singular.
However, contrary to other countries, the use of “vos” in Argentina also coexists with the commonly used “usted“, another form of the 2nd person singular. Many linguists have tried to understand the difference between one and the other, or in which contexts they are used, without coming to a definitive conclusion.
It is well known that there are provinces where “vos” is mainly used, such as Guanacaste and Cartago. Within San José there are regions where the use of voseo is the norm. But generally Costa Ricans inexplicably go between one form and the other within their everyday conversations.
For example, I know a family in which two sisters speak differently: one uses “vos” and the other uses “usted”. I suppose that if someone from another country heard that, it would seem strange to them, but in Costa Rica it is frequently heard. Conversations may happen in the following way:
—Hola, ¿cómo te fue?*
[Hello, how are you?]
—Bien, ¿y a usted?
[Fine, and you?]
—¿Vos viste el frío que hace?
[It’s cold, don’t you think?]
—Sí, acuérdese de llevar abrigo si sale.
[Yes, don’t forget to put on a coat if you go out.]
*Note that the first person in the dialogue uses the “te” and “vos” form, while the second person uses the “usted” form.
In my own case I’ve noticed that it is normal for me to refer to the person to my left using “vos”, while I talk about the person to my right using “usted”. It could even be that the person I have a closer relationship to the person I talk to using “usted”, which goes against the theory that “usted” is used to show respect or to generate a distance.