Certainly there could be more dialogue between John Proctor and Abigail. Her obsession with him and her willingness to destroy his wife to try and create a life with him has very rich dramatic potential, but the play does not offer a great deal of dialogue between them. This seems especially important since their connection underscores the nature of the petty, juvenile emotions that motivated the accusers. Jealousy or hurt feelings over being spurned by a lover are portrayed as sufficient reason to accuse neighbors of witchcraft and condemn them to public excoriation and execution. Along these lines, more dialogue among the young women revealing their petty jealousies and crushes could show how ironic their power and influence was. The film adaptation by Nicolas Hytner does explore this material somewhat further.
Miller does not give an extensive voice to the accused. Rebecca Nurse and John Proctor are given a voice throughout the play, but Miller could add additional dialogue to the characters of Martha Corey, Goody Osborn, and Sarah Good. Despite being considered social outcasts in Salem, Goody Osborn and Sarah Good's dialogue between the judges would provide additional insight into how the court functions. Also, there are gaps of silence between Giles Corey and his wife, Martha. The audience is aware that Giles feels extremely guilty for casting suspicion upon his wife, but there is no dialogue between the couple to give insight into their relationship. Miller could also provide dialogue between the girls who are under Abigail's control and accuse innocent citizens of witchcraft. Other than Mary Warren, these characters are never witnessed interacting with other characters away from Abigail. There is no dialogue between the girls to provide insight into their thought process and relationships with other community members of Salem.
A conversation could be imagined between John and Elizabeth Proctor after the debacle with their servant, Mary Warren, at the end of Act II. They must be worried and confused at the turn of events in Salem town.
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