Charles, in addition the Obese person should not be sat next to me either if in economy!
Up until a few years ago exit seats could not be booked prior to check in. It was at check in the agent would decide if you were suitable for the exit seats. Many a time I had a pre booked seat on Thai and then at Airport changed it to an exit seat. On no occasion was I challenged on language. just physical ability. It is I guess obvious in any language that an emergency is occurring and the door needs to be opened a bit pronto… I guess the language could come in to it more if the instruction is not to open the door. Better I guess to open and get it wrong than not open it and get it wrong. If in doubt, open the darn door.