The meaning of the word isn't very difficult to figure out, as the occasional bit of Spanish rarely is, and the context of it makes it fairly clear, but I wonder about its use. Throwing it in, to me, doesn't reinforce the cultural world that a character lives in--mostly it draws attention to the fact that it is written by someone who is writing in English. It reminds me, in fact, of an old comic character called Gambit. He used to show up in old X-Men comics with the worse Cajun dialogue, in which he calls every girl 'chere' and so on and so forth.
However, ignoring that, and returning to dialogue: I suppose the convention wisdom behind dropping in parts of other languages is to add authenticity, to further help the author build up his or her world. In theory, a few bits of Spanish or French or Japanese can do for you what a few hundred words here and there will do for world building and culture--at least, in a lazy fashion. I'm not yet convinced that it is nothing more than a shortcut that authors use in place of a real understanding of their topic--which, I might add, isn't a slam on the Le story, since I didn't have any real problem with the cultural building there, in as far as I knew much about Colombia. But still, when he dropped in the bits of Spanish, I did find myself thinking that they were unnecessary, and not doing him any favours.
Perhaps it's just me, though.