In The Crucible, who is Tituba and what is her relationship to the family?

Tituba is not actually a member of the family - so does not have a relationship to them in terms of blood, but Parris' black slave and a native of the island of Barbados. She seems to have been responsible for the girls as a "nanny" and she certainly cares for them all deeply.

Culturally, Tituba is extremely superstitious, and (in fact) does lead the girls in the dance that precipitates the events of the play as we see them. Tituba is also rather inarticulate, speaking mainly in a strong dialect, and quickly and easily dismissed by the supposedly more "cultured" court. Of course, in fact, they are behaving just as superstitiously as she is.