I don't see too many deaf people onboard entire aircraft. I am never seen all of those deaf people some my flight before. I knowable that I remember when I saw lady when I was on my plane during the flight from ATL-FLL years ago. She was used a sign languages. I don't concerns her during on my entire flight. You know that I am hearing impaired but, I don't qualified to sit there in exit row, am I right? When DL agent was change me to different seat in 20F during my entire trip from PHX-ATL-FLL last month. I am always understandable following the safety rules while I am not sitting in exit row seating, right?