By Catherine Saint Louis on August 17, 2015

DORAL, Fla. — Talking is a skill most children take for granted. But not in this classroom.

A dozen young children sit in a circle, dressed for pajama day. Some clutch their knees or a stuffed animal. A boy in Spiderman sleepwear looks worried but eager as he musters the courage to speak aloud.

“Who can be the first person to tell me what day it is?” asks Alejandra Golik, a student therapist leading the session. All the children, ages 6 to 10, know the answer.

After an achingly long pause, a 10-year-old girl mouths, “Thursday.” Her response is barely audible.

Still, it’s progress, and here the faintest whisper is applauded. It has been months, sometimes years, since these children have talked to anyone apart from family.

The children have selective mutism, an anxiety disorder, and they are terrified of talking in social situations. They may be chatterboxes at home, but at school or around unfamiliar faces, they are stone-faced and silent.

Experts estimate that roughly one in 140 children are selectively mute; most elementary schools have at least one student with the condition. Selective mutism can impede academic achievement and socialization, and lead to isolation and withdrawal from rituals like birthday parties and playground friendships.

The problem usually begins before age 5, and early intervention can help. Treatment usually involves cognitive behavioral therapy, with modifications for children who don’t talk to unknown adults — therapists included. If C.B.T. fails, drugs like Prozac may be prescribed in low doses.

But now researchers are taking a different tack: intensive, weeklong immersion programs, like this one run by Florida International University, in which selectively mute children are put through a variety of exercises to practice what frightens them most.

Classroom immersion may work more quickly than standard therapy, some experts say. And it exposes children to the need to speak in front of and with their peers.

“With six-hour days, they have time to process, adjust and practice multiple situations with repeated exposure,” said Jami Furr, director of the selective mutism program at Florida International’s Center for Children and Families. “The idea is to translate gains to a real school setting, where they have the most limited speech.”

Last month’s program run by Florida International enrolled 26 children who were split into two classrooms, one for elementary school patients and one for those younger than age 6. Out-of-town families arrived days before the classroom immersion for several three-hour sessions.

Each child was assigned an adult counselor called a “brave buddy,” and the first task was to try to speak to him or her. A parent was present until the listening therapist could slowly be brought closer. Later, during immersion sessions without the parents, counselors helped each child to navigate days of board games, scavenger hunts and other exercises gradually requiring them to answer questions and speak up. The classes culminated with a trip to a diner for hamburgers.

“We think of it as a bravery ladder where each rung represents a step of increasing difficulty, say, speaking to a new person, speaking in a louder voice, or maybe speaking in full sentences instead of one-word replies,” said Rachel Merson, a psychologist at the Center for Anxiety and Related Disorders at Boston University, which runs a similar program to treat selective mutism.

Dr. Yulia Perch, a psychiatrist from Long Beach, Calif., brought her son Leo, 9, to the Florida program. From the first through third grades, she said, he never spoke to his teacher or classmates.

“When he interacted with other children, he couldn’t share himself,” she added. “He couldn’t make jokes. He couldn’t reciprocate. It was just limited intimacy.” After his first individual session, Dr. Perch took Leo to a beach, where he and another boy discovered a raccoon and ended up talking about the bandit-masked animal and eventually Minecraft.

After the conversation on the beach, his mother said, “he understood the human reward.”

During the second session, Dr. Perch was astounded when Leo managed a whisper to his counselor. On his fourth day of the immersion program, he was asked the date in front of the group.

“The 30th,” he said distinctly, abandoning the modest whisper he had used just three days ago.

“He’s had this so long that I wasn’t sure he would talk at all,” Dr. Perch said afterward.

Children with selective mutism are often misdiagnosed; pediatricians, parents and teachers sometimes mistake mutism for shyness. But there are important distinctions.

A shy child is always reserved, even at home, but may warm up to a new person after a few minutes. A child with selective mutism may be outgoing at home and never warm to strangers.

Delayed treatment can exacerbate the problem, experts say. “Every day you are not better you are getting worse and getting better at being an avoider,” said Steven Kurtz, a psychologist in Manhattan who treats selective mutism.

Melissa Shattuck, of Huntsville, Ala., was shocked to discover that her chatty 6-year-old, Lily, hadn’t spoken a word to classmates at a holiday party. The girl’s teacher had assumed Lily was withdrawn at home, too, Ms. Shattuck learned.

“We saw two different Lilys,” she said. Only after the party did Ms. Shattuck realize that her daughter needed treatment for selective mutism.

Immersive programs now exist in several states. Dr. Kurtz helped start one at NYU Langone Medical Center and another at the Child Mind Institute in New York. Richard Gallagher, a director of the selective mutism program at NYU Langone’s Child Study Center, said weekend sessions would be held this fall at a campus in Hackensack, N.J.

In October, Dr. Kurtz plans to post free online educational videos for parents, teachers and caregivers who wish to help children with selective mutism.

Even after intensive help in the Florida program, some children weren’t able to speak audibly. By week’s end, four of the 26 were still struggling to speak aloud. “Some take it and run with it, and for others, it’s baby steps,” Dr. Furr said.

On the last day, many of the children were able to order burgers and fries on their own at the diner. But Elizabeth, a 6-year-old redhead from Texas, only whispered her order to her counselor, who relayed it to the waitress.

When the food arrived, Elizabeth was unable to tell another counselor that the chicken nuggets were hers. Given an iPhone that held recordings of her saying “yes” and “no” captured by her parents, Elizabeth pressed the yes button, then dug in.

“It’s definitely frustrating that we didn’t see more progress,” said Jonathan, the girl’s father, who asked that the family’s last name be withheld for privacy’s sake.

“On the other hand, with just four lead-in sessions and a week of school, she’s talking to someone she had never met,” he added, brightening a bit. “It’s huge.”

From the New York Times