One of the most colorful aspects of Spanish as it’s practiced in Buenos Aires is the slang or lunfardo.
Originating out of the working class immigrant neighborhoods in Buenos Aires in the late 1800s, lunfardo became a rich language and its influence is recognized in the writing of tango lyrics.
The result is that today Buenos Aires has many slang words that are not heard in any other Spanish speaking country.
The Dictionary of Argentine Spanish (in Spanish) provides many interesting slang words and their translations.