Often, normal refers to the people in power. It's normal to act the way high society does. Like, on a national level, the way that CEOs and politicians dress and speak is normal. Everything that deviates abnormal.
Normal can also be whatever the majority of people do. If you are in a heavily Cuban area, speaking Spanish is normal. If you're in Montana, Spanish is abnormal. (This could also be due to the fact that the majority of a people collectively are in power, therefore the first principe still holds true.)
Normalcy is always a good subject to explore. When we are young, we desperately struggle to be normal. And as soon as we grow up, we wish to be anything other than normal.