Wow, it's unbelievable story!
Perhaps, in one day, your parents lose their hearing. You could wave your hands in front of your parents' face. I know it was an insult, but they said that to you. I can't believe that they are jerk.
It turns me off when a speaker at a conference talks too fast that often forget to talk slow down because an interpreter had a hard time to catch up. I wish that I could do something to torture the speaker so that he/she learns a big lesson. Hmm, I can't tell you what methods that I could use for the speaker. 
