Sam King felt paralyzed. His heart was pounding so hard, the junior at Lake Region Union High School in Barton thought he was going to pass out in his psychology class. Sam and two of his classmates had to put on a skit. He had practiced saying his lines during rehearsals: "I'm in class. I can't check my phone right now." But the 16-year-old felt the familiar block in his throat. He took a deep breath and tried to force the words out. He eventually ran out of breath and had to start again.

But instead of saying his lines, Sam blurted out: "I have a stuttering problem. And it makes it hard for me to talk." He then asked his friend Trent to say both of their lines.

"I was so horrified with myself and the situation," he later recalled. While his classmates continued with the skit, Sam "blacked out," he said. Even so, he was glad he had told his classmates and teacher about his stutter. "It felt good as I was sitting down," he remembered. "The amount of relief I got outweighed the embarrassment."

Sam is among more than 70 million people worldwide with a speech disorder characterized by repetitions, prolongations or blocks. That's about 1 percent of the population, according to the Stuttering Foundation of America. "Instead of taking the superhighway to get the idea from your brain to your mouth, it might take the slower, country road," explained Dr. Danra Kazenski, clinical assistant professor of communication sciences and disorders at the University of Vermont.

Despite years of research, no one knows exactly what causes stuttering, though possible factors include genetics, child development, neurophysiology and family dynamics. There's no cure, either, but there are various treatments, including speech and cognitive behavior therapy and support groups.

Along with Dr. Barry Guitar, Kazenski is the coleader of the Burlington chapter of the National Stuttering Association, which organizes support group meetings for school-age kids and their parents, as well as for teens and adults.

"Of all the ages we're trying to support, the teenage group is the most likely to rather not address their stuttering directly," said Kazenski. "We have teens who've come, but they're uncomfortable."

"By the time you're a teenager, you've probably had years of fear and avoidance behavior," said Guitar, who also stutters. It's not unusual for teens to trade speech therapy for sports practice and other after-school activities. But, he added, it's also "very, very, very common" for them to seek treatment again when they're about to go to college or enter the job market.

Sam's parents began to notice that his speech was disfluent when he was a preschooler. They took him to a pediatrician, who told them Sam was just trying to hold their attention. According to the Stuttering Foundation, stuttering is part of normal language development in kids between ages 2 and 5, and 5 percent of all children go through a period of stuttering that lasts at least six months. Three-quarters of those will recover by late childhood, but 1 percent will continue to stutter into adulthood.

When Sam was in sixth grade, he wanted to invite a friend over but refused to make the phone call himself — it's common for people who stutter to avoid using the phone because of the time pressure, and because they can't see the listener. That was when his parents realized Sam's stutter hadn't gone away. Instead, he had developed a bag of tricks to help him get by, such as avoiding words that begin with hard consonants including d, c, t, g and k, and instead using words that were easier for him to say.

"I tried to hide it as much as I could," Sam said, noting that he was most afraid of stuttering in front of his teachers. "I'm not sure how they'll react. They might think I'm not as smart. Or I have a mental issue," he explained.

"People don't know what's going on," the teen continued. "A lot more comes with stuttering. It's not just the speech part. Like, worrying all the time, exhaustion from word swapping. Having to do that every day. All day."

Just talking at all could be draining for Sam. "I lose eye contact. I feel it in my throat. The word wants to come out, but it can't. It feels there's a wall in my throat. I lose my breath. After a long break, I run out of breath," he said, between pauses.

So, for the next two years, Sam met with a New Hampshire-based speech therapist in St. Johnsbury because it was the midpoint for both of them. "I was hoping to be fluent," Sam confessed. He was taught to exhale a little bit before speaking to slow down his rate of speech. But Sam felt it was too tiring to keep using the technique. When he entered high school, he got busy with sports practice and stopped going for speech therapy. But his stutter hadn't gone away, and he continued his avoidance behavior.

The tipping point came when Sam was a sophomore and took English honors. After his first class, he told his mother, Barb Limoge-King, that he didn't want to return. He wrote a three-page letter to his parents because he wanted to let them know how he felt.

"The reason I worry, I don't want people to think I'm different," he explained later.

"He was worried about the future, thinking about job interviews, meeting his girlfriend's parents for the first time, saying his wedding vows," recalled Limoge-King, who is a guidance administrative secretary at Lake Region Union. "I had no idea he was going through all of this. I burst into tears," she added. "I had my husband read it. He burst into tears. We thought everything was OK."

Limoge-King credited Sam's guidance counselor for helping him understand that his stutter didn't define him as a person and that it shouldn't prevent him from achieving success. Although Sam was hesitant, both mother and son attended the teen support group meeting in Burlington, two hours from their home in Barton.

"In individual therapy, we will target personalized goals," Kazenski said, noting that clients "will have structured home practice that we will send home with them." Support group meetings "address self-acceptance" and are "more informal," with participants sharing their experiences and making connections.

Kazenski estimated that some 6,000 people in Vermont stutter. But for most participants, attending the support group is the first time they encounter other individuals with the disorder.

A familiar face at the UVM meetings is Ben Manning, 24, who is training to be a speech language pathologist at the university. He's the student leader for school-age kids, but he attends the meetings for the teen and adult groups, too.

Like Sam, Manning stopped going for speech therapy when he entered high school because he wanted to go to ski practice instead. Manning said that since most kids develop speech normally, "if you do not, then you see yourself as different and not as good as everyone else."

At college, Manning chose to major in geology because the coursework didn't require many oral presentations. After graduation, he said he couldn't even apply for jobs because he was too afraid to talk to employers. That was when he decided to join support groups and resume speech therapy.

Today, Manning doesn't hide his stutter, and he consistently uses techniques when he talks. One of them is "fake" stuttering, which desensitizes him to his stutter. "I can do speech techniques all day in a therapy session. 'Cause that's wh-, where, where you start," he said. "The trick is, the mi-, minute you change environments, you have to kinda relearn how to do those things in those environments." Manning added, "I, I, I still feel uncomfortable when I'm caught in a stutter, erhm, because of social and emotional condi-di-di-ditioning from it."

Meeting Manning was "awesome," Sam said. "His attitude is just amazing. He tries to laugh about it," the teen remembered.

"My main thing is try to m-m-m-make it seem OK and, like, cool," Manning said.

The other teens also helped Sam feel less alone when they shared their experiences and struggles with their stutter. But the four-hour round-trip commute and Sam's sports practice prevent the Kings from being able to attend the support group meetings more regularly.

Fifteen-year-old Mary Hoyt from Orleans has also made a connection with peers in the Burlington support group. "But they live far away," she said, adding that she would like a group closer to home. Her mentor, also a person who stuttered, was planning to create support meetings in the NEK until his untimely death last year in a motorcycle accident.

Monica Menard is a speech language pathologist at the Orleans Central Supervisory Union, which includes Barton, Glover and Orleans. She has identified seven students in her district who have a stutter, though not all of them choose to get speech services. Menard introduced the Kings to the Burlington teen support group and took Mary to one of the meetings, as well. Menard said participating in the Burlington meetings through Skype is also an option.

But, she added, it's also important to increase awareness of stuttering among teachers, peers and the larger community. The disorder tends not to receive the attention given to cognitive and physical disabilities. And, suggested Menard, stuttering may not always be diagnosed.

Judy Hoyt, Mary's grandmother and guardian, said a support group for parents in northeastern Vermont would be beneficial for her. "I want to know what other parents learnt. Maybe there's some [way] I can help out more," she said.

Hoyt admitted it wasn't always easy for her to watch her granddaughter struggle. "First thing I want to do is answer for her, to make it easier for her, but that's not the answer," she acknowledged. "It's very hard, sometimes, for me to be quiet and let her get out what she needs to get out." But now Hoyt allows Mary "to go at her own speed when she's talking" and doesn't interrupt her.

Mary started getting speech therapy when she was in third grade. But being pulled out of class made her feel self-conscious, and she was a target of bullies. "Mary was begging to be sent to a different school," Hoyt recalled.

By eighth grade, Mary had stopped going to speech classes. She doesn't use the techniques she was taught because her mind goes blank when she stutters. Instead, she's found new coping methods. For example, when she's introducing herself, Mary prefers to be brief: "I say, like, erhm, I say like, erhm, 'Mary, from Orleans.' Erhm, and 'I like singing, songwriting and that's it.' So I don't, so I don't say, so I don't say, 'I'm, I'm Mary. And I'm from Orleans.'"

During reading class, the young singer-songwriter listens to music on her phone with one earbud. She t old her teachers that doing so allows her to focus less on her classmates, and she doesn't have to worry about them looking at her. "They said I could 'cause it helps me as long as I'm pay-, paying attention in class," she said. Mary's playlist includes "Let It Go" from the movie Frozen. "It, ehrm, it talks about her, erhm, not, erhm, worrying about herself, and so, and so that helps."

Now that Mary is a freshman at his school, Lake Region Union, Sam said he feels "less isolated." Like Mary, he made a class presentation on stuttering, and he talked to some of his friends about his stutter. But he said some people still finish his sentences for him.

"They probably think I need help," he said, adding that people should "just be patient with us."