I don't think you mean it this way, but this is a good example of what I posted about earlier. You said in some circumstances, she speaks "well" and in other circumstances, she speaks "ghetto." There's an implied judgement in there that speaking "ghetto" is NOT speaking "well." In realty, she is just fluent in two different versions of the language and is able to code-switch. One is not superior to the other, they just have different uses. It's no different than someone speaking English in public and another language in the home.