If the question is about the tango argentino compared to international tango:
Obviously, the music is different. International tango is usually danced to a steadily rhythmical interpretation of the music, with a stictly defined count of beats per minute. In tango argentino, however, nothing is standardized and there are different styles of music, usually associated with certain dates and orquestas: some are rhythmical (D'Arienzo, Biagi..), some romantic and soft (Caló), some very elegant (Di Sarli, Sassone) and some extremely elaborate (Pugliese). With different musical style also the style of the dance changes. What some call nowadays the "milonguero" style is most likely to be danced to D'Arienzo, while Di Sarli is often chosen by dancers who prefer the elegant walks of a style called by some "tango de salón".
Another big difference is that the international tango, even when danced in a social context, heavily relies on a syllabus of standardized figures. Socially danced tango argentino is usually improvised. Figures may be used as a tool to explain and teach techniques, but the goal is to actually get away from figures and to learn to improvise. This is one of the reasons why a syllabus would not make much sense here. However, there are commonly used names for frequently used movements and combinations which, again, show a great variability.