Spanish was established in the Río de la Plata region with the founding of Buenos Aires in 1536, though early colonization was sparse and the area remained a frontier until the eighteenth century. The Rioplatense dialect — spoken in Argentina and Uruguay — is distinguished above all by its use of voseo, the second-person pronoun 'vos' with its own conjugation forms, a feature that was common in Golden Age Spanish but disappeared in most of the world. Massive waves of Italian immigration between 1880 and 1930 profoundly shaped the accent: the characteristic melodic intonation of Buenos Aires Spanish closely resembles Neapolitan Italian prosody and differs noticeably from Castilian or Mexican Spanish. Lunfardo, a slang dialect that emerged in the immigrant working classes of Buenos Aires at the turn of the twentieth century, drew heavily from Italian, Genoese, and other European languages, and many of its terms have since entered mainstream Argentine Spanish. Today Argentina's approximately 45 million Spanish speakers use a variety internationally recognized for its distinctive 'zh' or 'sh' pronunciation of ll and y, and its rich lexical mixture of indigenous, Italian, and standard Spanish heritage.
