Jeff Daniels speaks and signs his dialogue in CBS movie 'Sweet Nothing in My Ear'

LOS ANGELES) " Hunched at the bottom of a staircase on a bustling movie set, Jeff Daniels practices his second voice.

His hands speak loudly as he rehearses sign language for "Sweet Nothing in My Ear," a Hallmark Hall of Fame telefilm about a married couple torn apart when their young son loses his ability to hear.

"Every finger has to be in the right place," says Daniels, who co-stars with Marlee Matlin in the movie, which premieres Sunday (9 p.m. EDT) on CBS. Daniels, who had never signed before, simultaneously speaks and signs his dialogue throughout the film.

In a series of heated scenes, Daniels' fingers fly as his character, Dan Miller, who is hearing, and his wife, Laura (Matlin), who is deaf, clash over whether young Adam (Noah Valencia) should undergo cochlear implant surgery. Dan presses for the procedure, which involves placing an electronic device in the inner ear, while Laura adamantly rejects it.

The couple's conflict reflects the real-life controversy over cochlear implants, considered a rejection of deaf culture by some members of the deaf community. But for director Joseph Sargent, "Sweet Nothing" is as much about a fractured family as it is about cochlear implants.

"What's going to happen between these two people who love each other?" says Sargent, who directed "Love Is Never Silent," Hallmark's Emmy-winning 1985 TV movie about a deaf couple and their hearing daughter. "How are these people going to resolve hanging on to that beautiful little boy and to each other?"

Relaxing between scenes, Daniels, 53, praises the evenhandedness of the script, written by Stephen Sachs and based on his play of the same name. "On my character's end, why wouldn't you do the very best you could for your kid?" he says. "What if he could hear again?"

"But my wife's answer is, 'So what you're saying is, he's not normal, he needs to be fixed. So am I not normal? Do I need to be fixed?' There's a whole deaf culture that wants to be considered normal " and they are," says Daniels, whose movie credits include "Terms of Endearment," "Good Night, and Good Luck" and "Dumb & Dumber."

A crew of sign language interpreters were on the set to assist Matlin and the company's other deaf actors, including Valencia, and Ed Waterstreet and Phyllis Frelich, who play Laura's parents.

An interpreter also assisted production consultant Linda Bove, who is deaf herself, communicate with the cast and crew. One of Bove's responsibilities was to make sure the actors' hands didn't drop out of sight of the camera while they signed during scenes. She also coached Daniels as he immersed himself in sign language for a few weeks before and during production.

At home in Michigan, Daniels reviewed online video clips of Bove signing his dialogue while an interpreter voiced them. Then he worked with Bove one-on-one for a few days in California before rehearsals started.

"When I read the script I said, 'I could blow this, I could just completely fail miserably,"' he says. "You've got these emotional scenes and yet it's like you're also juggling three peaches."

In one scene, Daniels talks as he carries a cardboard box into the Millers' house. During rehearsal, he carried the box into the house, then realized he needed both hands to sign his dialogue.

"Jeff's face went ashen white," Sargent says. Everything stopped while Daniels and Bove worked out a one-handed signing protocol. Such rethinking of staging and props was routine on the set, he says.

"Sweet Nothing" also challenged Matlin, who had never played a character who signed solely in American Sign Language, which has a different syntax than spoken or signed English.

Although Matlin, an Oscar winner for 1986's "Children of a Lesser God," routinely lip-reads, speaks and uses a hearing aid, she does none of these in "Sweet Nothing" because they don't suit her character, she says.

Rather, the 42-year-old actress signs silently in the film while an unseen actor voices her dialogue. Other deaf characters are "voiced" in similar fashion.

"I'm constantly making sure with Linda, 'Is this right, does this look good,' because I want it to be authentic," Matlin says. "I'll have a very tough crowd watching me."