Can anyone help me with castellano/lunfardo?
Well I'm supposed to be going to argentina for a semester and from what I hear the spanish there is very different from the spanish taught in your average high school or college class. Help please.
Castellano is just a term some people in South America (and other places) use instead of Spanish to indicate that they're not from Spain. It's kind of like saying I speak American instead of English. Ironically, Castellano actually refers to a region of Spain.
The biggest differences with Argentinian Spanish/Castellano are that the ll sound is more like a soft Portuguese j (as in Rio De Janeiro) instead of the y sound, and they use the vos form. Study up on the latter a little. Every area has its idiosyncrasies. Argentina isn't unique in that respect.
You're on your own with Lunfardo. I'd never heard of it until now.
Lunfardo is, for all practical purposes, unintelligible to an average Spanish-speaking person from any other country.
You'll be fine once you get used to the 'vos' form (instead of tu) and differences in pronounciation -- as the other repondent pointed out, in Argentina, the ll is either a j-sound (or in Buenos Aires) a 'sh' sound. There are of course a lot of words that are different. We don't say platano to name only one example, but generally if you have decent college spanish, you'll make yourself understood and you'll understand most of what is said to you.
As for lunfardo, unless you plan to translate tangos, you needn't worry. You'll pick up the idiomatic spanish quickly.