In certain parts of Latin America it's common to use the pronoun vos as a 2nd person singular pronoun (equivalent to the subject pronoun tú) with a sometimes unique conjugation. Voseo means using vos where Peninsular Spanish uses tú.
Vos is commonly used in and around the Río de la Plata area (i.e., Argentina and Uruguay) as well as Eastern Bolivia, Paraguay, and Central America (El Salvador, Guatemala, Honduras, Nicaragua, Costa Rica, southern parts of Chiapas in Mexico) and some parts of Colombia.
Vos and tú share the same conjugation in most tenses except for El Presente and El Imperativo where spelling and word stress are different. Have a look and listen to the following contrasting examples:
How and when you use vos depends on where you are and who you are talking to, as in some regions it co-exists with tú. For example:
- in Argentina, Uruguay and most of Paraguay, vos is the only informal pronoun. The use of tú is unusual and sounds odd.
- in places like Guatemala and El Salvador, the choice between tú and vos is a matter of prestige and social class, with tú being the prestigious and educated choice which is taught at school and vos being informal, considered even as a substandard form.
- in some parts of Colombia the opposite might happen; vos is the middle-ground choice between informal tú and formal usted.
Regardless of the regional variations, it is said that two thirds of the population of Latin America uses vos.