Hawthorne characterizes Pearl as "otherworldly" for almost the entire novel. Having no relationship with her unacknowledged father leaves her "half-human;" Even the governor describes her as "a little baggage that hath witchcraft about her." She, like Hester, is removed from the Purtian community in a small sense and humankind in a larger; it is only after Dimmesdale acknowledges his family does Pearl, watching her father die, cry for the first time, and becomes fully human. See link for more:
There is an old rock'n'roll song entitled, "Walk a Mile in My Shoes," that dealt with the same idea that is more eloquently expressed by Hawthorne. One must share in experience and sadness with others in order to understand others and, thus, be human.
Pearl, isolated from contact with other children, has experienced no sickness, no rejection, no companionship--none of the human communion that brings an understanding of others. Hawthorne writes, "she wanted...a grief that should deeply touch her..." Pearl lacks any of the experiences of failure and rejection that cause people to grow and connect with the rest of humanity. One's sorrows are the other side of happiness. Without sorrow, people cannot be fully human. This idea is underscored in Huxley's "Brave New World" where, in the interest of "social stability" people are spared unhappiness by popping soma anytime they have a disturbing thought. As a result, they are completely dehumanized and feel nothing when faced with death, age, brutality, or other human conditions.
It is when Pearl gets her mother and father to accept their sins, that she becomes fully human and is able to move away from the town, marry, and live a normal life. (Allude to your other questions.)