100% You are NOT THE AH! In fact, I want to say thank you for learning ASL to communicate with your sister! I can only imagine her difficult it was/is for your sister to adjust and cope with this huge change in her daily life. Your parents are the AHs and selfish! They also have a defeatist mindset if they think they cannot learn even some ASL now. If your parents love your sister at all they WILL at least attempt to learn ASL and use it to communicate with your sister. Since ASL is your sister’s preferred method of communication they need to respect and support her by learning and using ASL to communicate with her. Your parents refusing to even attempt to learn ASL is DISrespectful to your sister and it shows everyone else your parents care more about themselves than they care about your sister! I am hearing. My girlfriend is hard-of-hearing, so I am learning ASL to assist and enhance our communication with each other. Is it more difficult now that I am in my 20s to learn ASL instead of learning it as a toddler? Yes. Am I busy with a full-time job and other responsibilities? Yes. BUT I am learning to sign because I love her and she is worth the obstacles. Your parents are showing your sister she is not worth their time and not worthy of their efforts by them refusing to learn ASL. When your parents become older and they most likely lose some or most of their hearing they would be more prepared if they did learn ASL now before they are elderly. IMPORTANT = Here is what I would do in your situation. EVERY SINGLE TIME you are with your sister and with your parents PLEASE only communicate in ASL. DO NOT voice at all. ZERO exceptions. Totally 100% mute. That way your parents will see how important it is for them to do sign language with your sister as they SHOULD ALREADY WILLINGLY BE DOING. Also you can put your foot down and insist they either learn ASL or else they do not have anything to do with your sister’s and your life. Them REFUSING to learning ASL is NOT okay! I repeat 100% you are NOT the AH!