As twilight descends over Lake Simcoe, just outside Toronto, Marlee Matlin anxiously prepares for a scene in her first major undertaking since her Academy Award-winning performance in 1986's Children of a Lesser God. She has been nervous all day, vacillating between sulky periods and energetic bursts of baseball tossing. Now she is focused inward, singing to herself softly, "Row, row, row your boat..." When the cameras roll, her voice, though oddly cadenced, is clear and resonant with emotion. "Excuse me," asks a baffled bystander, "is that girl still deaf?"

The question is a testament to the surprising success of Matlin's latest achievement. Profoundly deaf since 18 months of age, the 23-year-old actress, whose speech was always difficult to understand, is facing her greatest professional challenge. In A Bridge to Silence, a CBS-TV movie that airs this Sunday (April 9), Matlin takes on the first speaking role of her career.

In so doing, she is not trying to distance herself from her condition. After offending some members of the deaf community last year by speaking rather than signing while presenting an Oscar, Matlin makes it clear that no repudiation of deafness is intended in Bridge. "I'm happy with who I am," she says in her vibrant combination of sign language and speech. "You wouldn't want to be a deaf person, would you? You're used to being the way you are. I'm used to being myself."

She does, however, want to separate herself from the character she played in Children—the obstinate, volatile Sarah. "I want roles without anger and feistiness," says Matlin, a demonstrative, uninhibited, often profane woman whose curses seem less offensive because they're signed. "I want to show weakness and sadness, some love, some happiness."

In A Bridge to Silence she does. Matlin plays a young deaf woman, the mother of a hearing child, who must fight the attempts of her embittered hearing mother (Lee Remick) to take the child away. To prepare for the role, Matlin stepped up her sessions with Dr. Lillian Glass, a Beverly Hills speech-and-voice pathologist who has coached Dustin Hoffman and Rob Lowe. "She had to marry her breathing and her talking," says Glass. "Being able to control her pronunciation opened up a whole new world for her."

It was a high fever due to measles, combined with a plane trip, that left Matlin deaf in both ears. Using a hearing aid, she has 20 percent hearing in her left ear and can make out the sounds of trains, planes and her favorite musicians, Billy Joel and Diane Schuur. Marlee began learning to sign when she was 5. "I spoke well enough to get by," she says through an interpreter. "But it wasn't perfect. I was talking through my nose instead of using my tongue."

No longer. "It's as if Marlee just had an accent," says Bridge director Karen Arthur. "After a while you don't have any trouble understanding her at all." It was when the hearing members on the set tried to sign that communication became tricky. Once, when Arthur motioned what she thought was, "That's beautiful," Matlin looked at her in bemusement and said, "I was wolf?"

Written with Matlin in mind, A Bridge to Silence is a sign of the clout the Oscar-winning actress now has. "I never could have gotten a movie like this produced without Marlee Matlin," claims executive producer Stockton Briggle. The statuette has given Matlin stature, but it hasn't, she says, "changed my life. I didn't get into this big head trip and spend all my hours kissing my Oscar. It's at my parents' house. I'll let them be proud of it."

Also relegated to the background these days is ex-beau William Hurt, her co-star in Children. "Certainly he learned from me, and I learned from him," says Matlin, who lived with the actor in 1986. "We are still good friends." As for the lawsuit by Hurt's ex-lover, Sandra Jennings, charging that he physically abused her, Matlin refuses any discussion.

A more recent romance, with MacGyver's Richard Dean Anderson, has also been put on the shelf. It began in Calgary, when they met in an elevator during the Olympics and she asked him to go skiing. How it ended "is not important at this point," snaps Matlin, sitting like a folded origami bird, her booted feet tucked under her. "I'm not married, I'm not getting married, and I have no kids at this moment."

Which is not to say she hurts for male companionship. Henry Winkler remembers "a coterie of young men" coming to visit Marlee last year when she lived in his San Fernando Valley guest house. Relations between Matlin and the former Fonz, it should be noted, are strictly platonic. The two met 11 years ago near Matlin's native Chicago at a benefit for the deaf. Winkler was so moved by her performance that he came backstage and signed, "I love you." Winkler, says Matlin, "was the one who told me that if I want to be an actress, I should go for it and trust myself. I've kept that thought with me ever since."

Improving her speech has given Matlin a great deal more patience and self-confidence, she says. It has also brought opportunity. She recently made a breakthrough when she was offered the lead in a romantic thriller, Catfish Tangle, a role originally written for a hearing actress. While waiting for that movie to film, she is working with the National Captioning Institute, asking celebrities to petition for closed captioning for TV shows and videocassettes. "I'm tired of seeing listings of programs I want to watch that aren't closed captioned," says Matlin, whose Bridge to Silence will be. "And I'm tired of looking for the symbol on the side of the video package."

Matlin spends her downtime with her cats, B.J. (Billy Joel) and Booty, in her new one-bedroom apartment in L.A. She's an avid hockey, football and base-ball fan who brings her own mitt to locations. But her spare time might be limited in the future. With her new versatility, she says, producers "are more open than ever before" to hiring her for roles that would have seemed impossible a few years ago. And Matlin's success sets an important precedent for other deaf actors. "There is no excuse not to use the deaf community," she says. "They used to be kept apart from the rest of the population, but that cannot continue." Not while Matlin's up at bat.

—Patricia Freeman, Lois Armstrong in Los Angeles