New York’s Roundabout Theater Company is mounting a production of the Huck Finn-based musical Big River this summer, with a groundbreaking twist. The show is aimed at deaf and hearing-impaired audiences, with the actors using a mix of singing and signing to tell the story. “The deaf learned to feel the music they couldn’t hear; hearing actors spent months learning American Sign Language.” The show’s director says it isn’t a gimmick, but a concerted effort to bring American theater to an audience that is ordinarily ignored by the industry.