A research has shown that Rioplatense Spanish, and particularly the speech of the city of Buenos Aires, has intonation patterns that resemble those of Italian dialects, and differ markedly from the patterns of other Argentine forms of Spanish. This correlates well with immigration patterns. Argentina, and particularly Buenos Aires, had huge numbers of Italian settlers since the 19th century.
According to a study conducted by National Scientific and Technical Research Council of Argentina, and published in Bilingualism: Language and Cognition (ISSN 1366-7289), Buenos Aires residents speak with an intonation most closely resembling Neapolitan. The researchers note that this is relatively recent phenomenon, starting in the beginning of the 20th century with the main wave of Southern Italian immigration. Before that, the porteño accent was more similar to that of Spain, especially Andalusia.
Influences on the language
The Spaniards brought their language to the area during the Spanish colonization in the region. Originally part of the Viceroyalty of Peru, the Río de la Plata basin had its status lifted to Viceroyalty of the Río de la Plata in 1776.
Until the massive immigration to the region started in the 1870s, the language of the Río de la Plata had virtually no influence from other languages and varied mainly by the means of localisms.
Argentines and Uruguayans often state that their populations, like those of the United States and Canada, comprise people of relatively recent European descent, the largest immigrant groups being those who came from Spain and Italy.
European immigration
Several languages influenced the criollo Spanish of the time, because of the diversity of settlers and immigrants to Argentina and Uruguay:
1870–1890: mainly Spanish, Basque, Galician and Northern Italian speakers and some from France, Germany, and other European countries.
1910–1945: Again from Spain, Southern Italy and in smaller numbers from across Europe (Germany); Jewish immigration, mainly from Russia and Poland from the 1910s until after World War II was also large.
English speakers, from Britain and Ireland, were not as great in numbers as the Italians but were influential in industry, business, education and agriculture. In the case of the English immigrants, they were certainly influential within the upper middle class.