The more I know, the less I understand

So, my initial impression on returning to Santiago was that it was a lot easier to understand what other people were saying, after nine weeks of practice with my Spanish. And indeed, it is easier to understand what people are saying; but only when they're saying those things to me. Or, to any other gringo, I suppose. Chileans talking amongst themselves, however, are a whole other story. Before, I assumed they were speaking Spanish quickly, and that I just couldn't penetrate the flurry, especially given the national quirks of pronunciation like, oh, dropping most d's and s's and conjugating in the form of "como estai" instead of "como estas". Now that I'm better attuned to those quirks and have improved my vocab and comprehension skills, I can sometimes pick out a word here and there. Unfortunately, my increased ability to parse the flood has had the unfortunate effect of making it abundantly clear that there is another, much more difficult problem. Specifically, even with complete command of your standard Spanish dictionary I'd never be able to understand what they're saying, because in Chile there is a whole other dictionary's worth of slang, and it is employed constantly and by pretty much everyone. It takes more time than I've got even to decipher the words comprising this slang; in the meantime, it's just "[??????] spanish spanish [????] spanish spanish spanish, [?????]!"

Not that I'm complaining -- in fact the sophistication of the language around here is pretty awesome. Anyway I consider it progress that I can now isolate the [????] maybe 20% of the time. Coupled with the 50% of the time I can actually parse the isolated Spanish bits, and the 30% of those instances where I can actually understand what I've managed to parse, I'm proud to say my eavesdropping skill has progressed by some kind of decent percentage, which I'd calculate more accurately if my motivation to do math right now was anywhere over its current, easy-to-quantify rate of exactly 0%.