Cultural relativism and ethical relativism

What is cultural relativism? What is ethical relativism? What, if any, is the relationship between the two?
Do people outside of a culture have the right to criticize that culture’s values or beliefs? Why or why not?
Think of a strong example of a cultural practice. For example, say another culture practices child marriages. What would a cultural relativist say about this? What would an ethical relativist say about it? Support your answer.