Spanish is the official language in the Argentine Republic. It was brought by the Spanish conquerors; it underwent changes from its coexistence with the native aboriginal peoples that enriched it, especially in its lexical aspects. The successive immigration waves that took place in the course of the 19th. century and the beginning of the 20th. century also contributed to the Argentineans language. The dialectic differences in the territory, far from making communication difficult, enrich it, thus contributing to consider language as a “simplex” language, that is to say, such language which varieties are intelligible between each other. The Spanish language in Buenos Aires adopts lunfardo forms, a slang of Buenos Aires City.

The Araucans constituted an important Amerindian population nucleus of the Araucanian linguistic family. They lived in the central and meridian areas of Chile and the center and west of Argentina. In the Quechuan language they were called auca and in Araucan language: mapuche, that means people of the land. They speak chilidengu or mapudungun, which in turn have many dialects. The main araucanian surviving populations are the picunches, mapuches, huilliches and cuncos. With the course of time, the words araucano and mapuche have turned synonyms and their language is also named in this indistinct way. At present they live in communities in the southern area of South America, in the pampa and patogonia areas, struggling against snow and cold weather and claiming the ownership of their lands since historical times. In Argentina there are about two hundred thousand mapuches who, organized in over one hundred communities, keep their language and traditions alive.

When speaking about guaraní o tupí–guaraní, it is referred to the Amerindian population that was settled in the area of eastern and north–eastern Argentina, Paraguay, Brazil and part of Bolivia. Some historians locate them from the south of the Amazons river to the slopes of the Andes. Their languages were tupí and guaraní. Still today they are spoken in these regions, guaraní being the second official language in Paraguay. Since the 18th. century, a great portion of the native peoples have taken customs and traditions from the colonizers in the Jesuitical missions and after that religious order was expelled, they became integrated in various settlements. They traditionally called their language ñe’engatú ("precious language"), or abá ñe’é ("man language"). The guaraní language has given origin to many dialects as the carioca, the tupí, the cario and the caribe, among others. There are some symbols that cannot be reproduced by our Spanish alphabet.

Quechua is part of the quechumara (quechua + aimara) family spoken from the south of Colombia to the centre of Chile, passing through Ecuador, Perú, Bolivia and Northeastern Argentina. It includes around twenty dialects (at least three in Argentina) that are mutually understandable for its clear and simple grammar. In the Province of Santiago del Estero, a dialect of strong personality and rather different from other varieties of Perú and Bolivia is spoken. For some linguists, it is a non pre–Hispanic language that came in with the yanaconas indians brought by the Spaniards from Perú, while other researchers assert the opposite. Apart from the Santiago del Estero case, others are reported in La Rioja and Catamarca, spoken in rural areas until the beginning of the 20th century. The variety of the Calchaquíes Valleys, Salta and Jujuy Valley, still kept in some places should be added to those two.