River Plate Spanish is locally known as Castellano Rioplatense. It is spoken in and around the River Plate basin of Argentina and Uruguay. It is a dialectal variant or simply a dialect of the Spanish language. There are distinguishable differences among the varieties spoken in Argentina and Uruguay.
The language is mainly based in the cities of Buenos Aires, La Plata, Santa Fe and Rosario (Argentina) and Montevideo (Uruguay), which are the five most populated cities in the dialectal area along with their respective suburbs and the areas in between. It can also be found in other areas not regionally close but culturally influenced by those population centres, such as parts of Paraguay and all of Patagonia.
The Spanish Colonization by the Spaniards brought their language to the area. Originally part of the Viceroyalty of Peru, the River Plate basin became the Viceroyalty of the Río de la Plata in 1776.
The language had no influence from other languages until the massive immigration which started in the 1870´s . The following are the three periods of immigration:
1. 1870-1890: Immigrants were mainly Spanish, Basque, Galician, Northern Italian, French, German.
2. 1910-1945: This time there were Spanish, Southern Italians, and Jewish ones from Russia and Poland.
3. After 1945: British and Irish speakers influential in industry, business, education and agriculture.