I agree with a point Eliza made a bit earlier about how could society produce the views and intellect of the late Jade Goody when we claim to have an education system?
However, although on this thread I find myself agreeing with M'unlearned friend on a few of his points, I can't accept his idea that this is about choice. You are the net result of your experience and role models.
When I found myself having to influence and debate with people from other parts of the country, I found it a good practical idea to try and lose the South Yorkshire clipped dialect. My intellect hadn't changed, (I may not be the best judge of my intellect!) just the delivery.
Don't confuse language with attitude or choice.