The Piano Lesson was written by August Wilson, son of a white German-American father and black mother born in 1945. The play premiered in 1987 and opened on Broadway in New York in 1990. The story, though, is actually set in the 1930s, and thus the costumes and setting should reflect the period in which it was set rather than the twenty-first century. The setting is particularly important because it is during the Great Depression, a period of great and widespread poverty in the United States, when most families were struggling just to survive.
Although Maretha, Berniece’s eleven-year-old daughter, is a minor character in terms of her actual role in the play, she is crucially important for the way she represents the future of the family, and of African-American people. The main decision the older people in the family must make is whether she should be told of their history, and in a sense become burdened with a history of racism and oppression or whether she should be given a fresh start outside of that history.
Maretha's ability to see the ghost suggests that Wilson does not think that there is a real choice for black children to be raised in some way free of their background of racial oppression. Instead, her heritage is part of her, and can become an essential and creative part (symbolically represented by her learning to play the piano) rather than just a negative one.
I think that the family greatly loves and cares for Maretha, and that Berniece, even living in poverty, would have taken great care to hand sew Maretha's clothing, perhaps adding small elegant details such as a lace collar to blouses or dresses, to show her love and pride. She would have been concerned to raise Maretha as a "lady", meaning that Maretha would sit in what was considered a proper ladylike pose with her back upright, knees together, her legs neatly crossed at her ankles, and her hands folded in her lap. Her body language should not be that of a 21st century teen wearing jeans and slouching over a cell phone, but rather a young girl whose family takes great pride in her.