In his first book of stories since ''The Bridegroom, ''National Book Award-winning author Ha Jin gives us a collection that delves into the experience of Chinese immigrants in America.A lonely composer takes comfort in the antics of his girlfriend's parakeet; young children decide to change their names so they might sound more ''American,'' unaware of how deeply this will hurt their grandparents; a Chinese professor of English attempts to defect with the help of a reluctant former student. All of Ha Jin's characters struggle to remain loyal to their homeland and its traditions while also exploring the freedom that life in a new country offers.Stark, deeply moving, acutely insightful, and often strikingly humorous, ''A Good Fall'' reminds us once again of the storytelling prowess of this superb writer.