Read the excerpt from "Mother Tongue." I am a writer. And by that definition, I am someone who has always loved language. I am fascinated by language in daily life. I spend a great deal of my time thinking about the power of language—the way it can evoke an emotion, a visual image, a complex idea, or a simple truth. Language is the tool of my trade. And I use them all—all the Englishes I grew up with. How does Tan build a central idea of her story in the excerpt?