 It is spoken by communities in neighboring countries, including parts of northeastern Argentina, southeastern Bolivia and southwestern Brazil, and is a second official language of the Argentine province of Corrientes since 2004; it is also an official language of Mercosur.Guarani is one of the most widely spoken indigenous languages of the Americas and the only one whose speakers include a large proportion of non-indigenous people.This represents a unique anomaly in the Americas, where language shift towards European colonial languages (in this case, the other official language of Spanish) has otherwise been a nearly universal cultural and identity marker of mestizos (people of mixed Spanish and Amerindian ancestry).