mute?

Yesterday afternoon, I had spend time from 9am to 4pm. My son and I had a nice spend time together. I alway feeling that he should learn about an American-Singaporean culture. We went to hong kong cafe. We ordered the breakfast. I asked my son. Who was this famous photo? His fingers spelling said B r u c e L e e. the reason why is that he needs to know who bruce lee was. I also learned that one of his classmate was bullied my son as a NOT 100% Chinese as he was in Chinese classes. I told him to be cool and be smart. Bcs my son knows Chinese, English and America/Chinese sign language. In the sudden, the Chinese lady asked me " are you mute? (Chinese sign language) I told her "hmph, I was speaking in Chinese slang for busboy" and I yelled her a little " get back to work on yourself" a Chinese lady was shocking and noddles her head(ok ok) I told him that mute is wrong word for insult to deaf American. I agree that "knowledge will give u power, but Character respect" by bruce lee ;)