WASHINGTON - Teachers come to the classroom with noble goals: closing the achievement gap, illuminating young minds. But first they must confront a more pressing problem: how to manage children's urgent requests, in the middle of the most carefully planned lessons, for permission to sharpen pencils, get drinks of water, or visit the bathroom.

One solution, a growing number of teachers are finding, is learning to speak without sound.

"The very first year I taught, I realized how much time I was wasting in my classroom for my students to be constantly raising their hands," said Fran Nadel, 25, a second-grade teacher at Woodburn School for the Fine and Communicative Arts in Falls Church, Va. "I realized if they could do this without talking, I could send them somewhere with a flick of my finger."

Sign language has become a saving grace - a way to communicate without interrupting instruction - not just in her classroom but in schools across the country. Students sign the letter B for bathroom, W for water fountain, L for library - and Nadel, who devised the silent system when she was student-teaching four years ago, replies with a nod or by pointing.

"Sign language is the ultimate multitasker's tool," she said. "It lets you tend half the class' bodily needs at the same time you're helping a small group learn."

On a recent Wednesday morning, Nadel huddled with a reading group of four students while the rest of her students worked independently at their seats. Every so often, a hand would shoot up from the back of the room. Nadel would respond almost imperceptibly, and the reading lesson would continue uninterrupted as the student scampered off to the bathroom, pencil sharpener (S for supplies), or the trash can (the letter T).

Signing has long been a tool for teachers to help special-education students develop language skills, and for years it has been offered in area high schools as a second language. Now its use as a management tool appears to be on the rise.

Signing Time, a Utah-based business that has been selling how-to-sign DVDs since 2002, launched its first classroom edition this summer. And at Time to Sign, a Florida-based company that provides American Sign Language training workshops for teachers, sales of "classroom management bundles" of CDs and posters are up 300 percent in the last two years, owner Lillian Hubler said.

That growing appetite might be caused by the push for accountability, which means teachers are spending less time in front of the whole class, said Woodburn principal Bridget Chapin, and more time working with a few students at a time, grouped according to skill level. Teachers have to maintain a coherent lesson for those few students while managing the whole class - and talking, Chapin said, is often not the best way to do that.

"So many kids are so visual that words just wash over them," she said. "A lot of times, the more words you use, the less effective you are."

Teachers echoed that sentiment. Special-education teacher June Behrmann, who teaches kindergarten through second grade at Oak View Elementary School near George Mason University in Fairfax, Va., uses signs to communicate unobtrusively with her students when they are included in general education classes.

"I can prompt children without moving toward them," she said. "I can just say pay attention, and no one necessarily sees me."

Going silent can also save a teacher's voice and energy. "By October, I realized I couldn't keep up talking as much as I was talking," Sarah Zydney, a preschool teacher at Brent Elementary School in Washington, said of her first year in the classroom.

Now in her third year, Zydney, a former Teach for America fellow, led a signing-as-classroom-management workshop for new fellows over the summer and has helped train other Brent teachers to use common signs to ask students to sit down and allow them to go to the bathroom.

In Nadel's classroom, the number of students needing to get up for one reason or another decreased noticeably once small-group work gave way to a classwide game of Jeopardy! in review for a science test. Students have learned that whole-group instruction is not the time to ask for the water fountain, Nadel said.

But there is one thing they haven't figured out. Asked how Nadel sees all those hands in the air when she's in the middle of teaching a reading lesson, 8-year-old Kayla Sanchez Arevalo's eyes widened.

"That's something I don't know," she said.