From a psychological/behavioral perspective, what do you think of this cat's behavior? <Video>?

I think it's real. I've seen too many cats that can alter their own voices to suit their mood. She's being protective with a different voice, and then when she sees the owner, it's not embarassment, but she speaks to the owner in a different voice. Cats can, but they don't usually vocalize (meow) to other cats. They will however purr and trill to other cats, but meows are usually reserved for humans and other animals.