Troupe Lets Deaf In on the Action : Theater: Renowned National Theatre of the Deaf lifts curtain on live performance for the hearing-impaired.

In the theater, vocal intonations and music sometimes can mean the difference between comedy and tragedy. Yet in recent years, the theater has become more accessible to the deaf and hearing-impaired. Interpretive performances are increasingly common as more and more classical drama is being interpreted into American Sign Language.

But for the National Theatre of the Deaf, which will present its production of Robert Nathan’s “One More Spring” at the Plummer Auditorium in Fullerton tonight and at the Irvine Barclay Theatre on Wednesday, the important thing is not only to pull up the curtain on live theater for the hearing-impaired, but also to increase access to the stage for deaf actors.

In fact, only about 10% of the audiences attending the 25-year-old, Tony-award winning troupe’s performances are hearing-impaired, according to Mary Gallagher, its director of public relations.

“We are the only professional deaf touring theater company,” Gallagher said. “The actors can serve as role models for deaf children. It allows people to say, ‘Hey, I can be an actor--or I can be anything else I want to be.’ ”

Actually, the company is made up of both deaf and hearing actors, selected from participants at the theater’s annual summer training center and through auditions in New York City. “David Hays’ primary goal when he started the company (25 years ago) was not to start a theater for the deaf,” but to assemble a top-quality theater company, Gallagher said.

“It’s a professional troupe that just happens to have hearing-impaired actors,” she continued. “What we do . . . no other company could do better. Our motto is that ‘You Can Hear and See Every Word.’ ”

In “One More Spring,” 10 actors and a violinist take the stage; two of the hearing actors perform the speaking lines while the rest perform in sign language. The story, which revolves around a group of characters who decide to live off the land in Central Park during the Depression, incorporates violin music. Gallagher said that for audience members who can’t hear the music or spoken lines, the drama emanates from the movement and grace of signing.

“I think sign language seems to be a lot more expressive than the voice,” Gallagher said. “Because you don’t hear the screaming or the intonations of the voice, you’re left totally with the physical-ness, the movement of the sign language. It just translates beautifully to theater.”