Dose mrs flowers teach the young marguerite to ''sing?'' if so, in what way?

Yes, she does. Maya's retreat after the rape left her mute; it was the way in which she protected herself, it was a way to hide from the world around her. Mrs. Flowers brought her out of her shell and helped a distraught, young girl without hope return to the world of the living. She gave her a reason to live, and she gave her the tools to "sing." This book is a direct result of what Mrs. Flowers brought to Maya's life.