I don't think people really try to fit themselves to a certain stereotype. At least not most people.
I think how you act and talk has to do with the people and the kind of environment you fit yourself to. If you notice people that have been friends for a long time, you would most likely see that they tend to act, dress and talk the same. Kind of like accents. Have you ever known someone to move to a different part of the United States, like from the North and headed to the South? Within a couple months they begin to get that Southern twang in their speech.
I don't think it's stereotypical.