I would agree with what the others have said, but add that I think your family should try to react calmly when she does it too, perhaps just calmly saying her name once in a neutral tone of voice. I think if you give it too much attention, i.e. scolding or trying to reassure, she might be seeing that as reinforcement for the behavior. I'd definitely have her looked at by the vet first to rule out anything physical, and if nothing there try to find a behaviorist for a consult.

Good luck, I know this has to be alarming for you and your family.