The biggest difference in the Spanish spoken here as compared to the Tex-Mex I'm used to is that 'll' isn't the english sound "yah" but a softer sound somewhere between a "Shh" "Zhh". For example, calle isn't "k-eye-eh" but "ka-zhh-eh". I think I'm starting to get the hang of it- or at least understand what's going on around me.
For some reason, I find this difference really funny- and apparently the rest of Latin America does as well; Carlos told me today that when he went to Mexico people would come up to him and say "ohhhh, speak Argentinian to me! Hahaha.". But I think the zhhh sound is really ...pretty. Aside from being different and confusing, I think it softens the sound of Spanish- here it sounds a bit more like French or Italian than the Spanish I know.
Which makes sense considering that the Zhh sound comes from Italian. More than 60% of Argentinians are descended from Italian immigrants and so it's had a pretty substantial effect on the culture. In fact, in the 1980s there was a failed attempt to switch the national language to Italian.
It also has a bit of the lilting tone of Italian and (I can't explain this one, because I speak absolutely no French, but) I've noticed that some Argentinians speak English with what sounds to me like a mix of a Spanish and French accent.
So far it's proved pretty difficult to stop myself from reflexively saying "k-EYE-eh" (or "poy-yo" or "yah-vehs" -pollo or llaves) but I'm going to try and speak like a native while I'm here and acquire the Argentine accent.
P.S. They also pronounce the "j" similar to the English pronunciation "jcha" and although they definitely don't speak with the stereotypical lisp of a Spaniard, they do soften or drop the "s" at the end of most words. But I think those are more common throughout different parts of the Spanish speaking world.
P.S.S. Non-American friends: What does the American accent sound like?