This is a true story. I was talking with a scholar, author and professor from England. Some years ago he was working at a hospital and a man who was a Duke came in as a patient. He didn't know exactly what to call him, so he would simply call him "Sir." The Duke's wife came in to visit. My friend asked her, in her husband's presence, what he should call her. "I respond to Duchess," she replied. "Humph," said her husband, "Call her Susan."