Susan "Susie" Swanson is the daughter of Joe and Bonnie Swanson. Like Stewie, she is intelligent enough to understand everything that's going on around her. Unlike Stewie, she can't talk out loud, but she can talk in her head. In her head, she has the voice of Patrick Stewart. She also has the same personality traits as him, too. So, she's basically Patrick Stewart trapped inside the mind of a baby girl.