The creation of Argentina as a modern nation in the 19th century required the construction of a national cultural identity, and language was a fundamental element in this formative process. Lunfardo is the linguistic repertoire of Buenos Aires rooted in its immigration history and was one of the linguistic examples directly operated upon by that process. Though now it is a renowned and celebrated component of tango and the porteño speech, and thus of the entire Argentine culture, when it was first documented in Argentina it was merely depicted as a criminal jargon. This study analyzes some of these earliest descriptions of Lunfardo, and aims at identifying some of the ideological biases behind their interpretations. In this way, this paper hopes to shed more light on the role of this important linguistic phenomenon in the history of the creation of an Argentine national cultural identity.