The Lunfardo is a popular language or slang characteristic of the Rio de la Plata. It appeared during the second half of the 19th century, just as tango did, as a result the massive immigration and cultural mixing which accompanied the expansion of the city of Buenos Aires. It is mostly composed of italian words from the genoese, toscan, napolitan and sicilian dialects as well as other expressions of afro-brasilian, Spanish, aboriginal and gauchesco origin. 
Like any other argots or slang, the lunfardo is not a language in itself but a set of words and expressions which are not a part of the official language. According to Jose Gobello, who was the first to study the phenomenon in the 1950’s, lunfardo expressions were initially meant to be unintelligible or playful. Lunfardo is a voluntary transgression of the official language. 
It is often said that the lunfardo was “the language of the thieves” (the word “lunfardo” itself refers to “lombardo” meaning thief) though it was most probably and simply the language of the streets at a time when things could get rough in the suburbs and poor zones of the city center.
As the city of Buenos Aires continued to expanded and develop at the beginning of the 20th century the lunfardo became a part of the new urban culture. It was naturally present in the lyrics of the music which was born of the exact same urban context, the tango. It was immortalized in the rudimentary lyrics of pioneers such as Angel Villoldo as well as those of Pascual Contursi, Celedonio Esteban Flores and other poets the 1920’s.
During the dictatorship in the 1930’s the lunfardo was banned from all media in Argentina along with other improper language or allusions to undesirable topics.  As a result the lunfardo disappeared completely from tango lyrics during the golden age. When the prohibition was lifted in the 50’s it proudly reappeared in popular culture including late tango recordings and Argentine rock songs . The lunfardo had become a symbol of national identity and remains present in everyday language to the point of being integrated to or undistinguished from the official language.
The Academia Portena del Lunfardo was funded in 1962 to document the history and evolution of this phenomenon. Over 6000 lunfardo words and 3000 expressions have been identified from contemporary and historical sources. π
 Fraga, Enrique. La prohibición del lunfardo en la radiodifusión argentina 1933-1953. Buenos Aires: Lajouane, 2006.
 Gobello, Jose, and Marcelo H. Oliveri. Tangueces y lunfardismos del rock argentino. Buenos Aires: Corregidor, 2001. Print.
 Conde, Oscar. El lunfardo es un fenómeno linguístico único. Pagina12. Online. https://www.pagina12.com.ar/105340-el-lunfardo-es-un-fenomeno-linguistico-unico
 Entrevista a Jose Gobello. Revista El Abasto. n .68, Aug 2005. Web. Sept 2016.