I just wrote a scene where some drug dealers talk to eachother about how to handle a problem they are having. Most people do not have experience with this sort of thing. Consequently, when writing it they have to rely on pre-existing cliches or extrapolate their best guess from what they DO have experience with.
Fortunately, I work with drug dealers every day, Monday through Friday. I know what they sound like when they are talking amongst themselves. The down side, though, is that their natural language sounds REALLY cliche.
I am joking a little bit, but it is an issue. The actual problem is that they way they actually talk would be, for the most part, unintelligible and unbelievable. What I end up doing is writing the dialogue "straight" and then peppering in a few slang constructions to give it a "realistic" feel.
In this case, clarity trumps accuracy. Plus, the characters in my comics live in a fictional city.....so who can say what "accuracy" even means there.