Tan's language concern

After reading the "Yes or No" by Amy Tan, i was finally be able to dissolve some of my misunderstanding about Chinese people. we always talk about their politeness which is not often refer as a appreciation rather sometimes it sounds as a wit. now, when i learn that they have no such word as yes or no, i was really fascinated by the idea that they can not express their opinion at first place as we do. But Amy Tan made it very clear that two different language does not have to mean the same meaning for same word.Therefor, in Chinese language , it might not necessary to put any direct word for specific yes or no. They just say it in a different way. And that does not mean that they don't know how to say no when they need to as Tan was saying,"There is no word for yes or no- but not out of necessity to be discreet. if anything i would say the Chinese equivalent of answering Yes or No is discrete, that is specific to what is asked."(pg-34)
i really like it when she talked about being a bilingual. she brought up in America but in a mainland Chinese family. so she know both language more or less very well. that's why she could question herself what she knows about language when she needs to compare between two language. i like her example about this matter. we really don't know much about our language.
While reading this one, a question popped out in my mind and that is why we akways compare other language with English?