Prime Stage Theatre’s season of premieres continues this weekend with a commissioned work by playwright Tammy Ryan, who has adapted the National Book Award finalist “Speak” for the stage. The YA novel about consent, trauma, and healing has frequently been near the top of the ALA’s banned books list since its 1999 publication.  “Some people are afraid to let teenagers, as Laurie would say, be exposed to the realities of the world,” Ryan said, quoting “Speak” novelist Laurie Halse Anderson.