My cat is a little over a year old and does not make any noise when she meows. She never has. She opens her mouth and to most people it sounds like she is hissing but she lets out a breathy little "ah" instead of a normal meow. It doesn't seem to bother her and I'm so used to her meows that her little "ah"'s even wake me up in the middle of the night. I've asked my vet but she didn't have ny ideas. Does anyone know why she can't meow?