In discussing this mother and daughter, I think the most important aspect of their relationship which so interferes with the development of a mutual understanding is that Suyuan Woo was raised in a culture (in China) where she knew things because she saw them practiced. Things were not spoken about or explained, but children were very carefully trained so that communication became unspoken. With little said between two people, the cultural knowledge they had "absorbed" was so similar that words were almost unncessary.
Enter Jing-Mei "June" Woo. She is growing up in a culture where communication is open and necessary to share ideas. The American culture is much looser than the Chinese culture. June does not understand her mother because she cannot understand the culture from which her mother has come. She has little respect for the life her mother led—which was a very painful one: for example, Suyuan had to leave her twins along the roadside during the war, hoping someone would care for them, because she thought she was dying...and actually almost did die.
The expectations of these two females/women are diametrically opposed because of their very different experiences. It is only when June is able to travel with her father to China, to meet her half-sisters (the "twins") that she is able to put her mother's life into its proper context: the ancient culture of China that has been so slow to change. Understanding comes to June after her mother's death, but unites her with her mother's spirit and the hearts of her half-sisters.
I think that in speaking of Suyuan Woo and June Woo, I would have to concentrate on their inability to communicate and understand each other which causes so much strife between them.
(I have included a website that explains their cultural difficulties with communication in more detail.)
I think that you have a couple of approaches that can be used in order to open your speech. Much of your introduction is going to depend on what your speech's focus is going to be. Specifically, what elements of the mother/ daughter relationship are you going to explain? Figuring this out will allow you to craft a meaningful introduction. In the case of June and Suyan, I am attracted to the idea of parents and children living in the shadows that haunt them. It seems that Tan is suggesting that in order to understand one another, both parents and children have to understand the shadows that plague one another. June is constantly followed by the shadows of her mother's expectations and the belief that she is "not good enough." For her path, Suyan is constantly haunted by the shadows of the children she sacrificed in China and what it meant to live a "dual consciousness" state of being, where America represented one part of her life and China, the other. In understanding these shadows, parents and children can heal many of the wounds that exist between one another, caused by a lack of communication and understanding. The metaphor of the shadow might be an interesting way to bring this out to your audience in your introduction.