Can you explain this social dialect example?

I'm no expert but I can only assume that it has to do with a class system. Being born in a poor, middle, or rich class, usaully in over 80% of the time, results in the manner of your speak, understanding of surroundings, manners, levels of respect towards others, especially authority, common sense,and education. There is that exceptional 20% few that will make the effort to educate themselves.