My cats name is Luna and she will turn when I say Luna, Luna tuna, Looney, my baby, Lil girl, I can't think of them all but she knows them as her name. When I call her sister she ignores me because she knows I'm not addressing her. Cats are smarter than most people give them credit. If a cat doesn't come when you call them or even acknowledge you then they are just being cats they ignore you when they don't want to be bothered or they are not in the mood. If my cat would always act weird or ignore me I would probably go get their ears check but yea unless they have a hearing problem they ignore when they want but they truly know their name or nicknames.