Your 11-month-old is sitting calmly in her high chair when she suddenly looks at you with wide blue eyes and starts to wail.

Parents and caregivers are using simple sign language to help infants communicate. The end result can mean less frustration for everyone.

Your 11-month-old is sitting calmly in her high chair when she suddenly looks at you with wide blue eyes and starts to wail.

You mentally tick off the possible reasons: A wet diaper? A stomachache? In need of a nap?

Then she balls up her fist and starts pumping her fingers, and you have the answer: She wants milk.

The "milking a cow" gesture is just one of a dozen or so hand signs that parents have begun using in the past two decades to help babies communicate before they can form words.

Being able to tell what your child needs is a huge help, said Hana Hales, who has used sign language with both of her young children and in her job as a day care teacher. "They definitely have communication skills, but just not verbally at that age," she said.

The sweet spot for sign language for babies seems to start around 8 or 9 months of age, said Krista Winner, a Nationwide Children's Hospital audiologist. That's when babies are agile enough to begin signing with their hands.

But teaching the signs can start months earlier, Winner said. "You can start on Day 1," she said. "The earlier the better. The more you repeat it and the more they see it, the more their brains will start to understand it."

She suggests parents learn signs for words that involve an activity, such as "more," "eat," "all done" or "bath," and then use the signs as they speak the words to their child.

"At bath time, do the sign for bath. When you put food in front of them, say and sign 'eat,' " Winner said. "If you pair it with your voice, they'll start to understand the meaning behind it."

Hales, director of the Barrington School of Hilliard, has teachers use sign language in the infant and toddler rooms at the day care center. "We've used it in every infant room I've ever been in," she said. "Parents love it and get excited about it. Some use it at home and some don't. But the children learn it quicker if they use it at home and at school."

Barrington teachers use about 10 signs, including "all done," "bottle," "please," "play," "sleep," "thank you" and "more," Hale said. "The kids could probably learn a lot more, but we tend to concentrate on the self-help signs."

Learning to sign does more than help a child communicate, said Bobbi Colatruglio, a speech therapist at Nationwide Children's. "It helps them understand that they can control their environment through communication," she said. "They see that if I move my hand like this, someone gives me milk."

When sign language for babies became popular in the 2000s, some experts worried babies might use signs rather than learn to speak. "But now we know that it actually helps with vocabulary," Colatruglio said. Signing teaches babies to think critically, so they realize that a word is a representation of something, such as milk, she said.

Morgan Bennett of Eastmoor used sign language with her two older children and is beginning to teach it to her youngest, 8-month-old Beatrice. Her oldest, 4-year-old Sam, had an articulation speech delay as a toddler and signing allowed him to communicate when his words couldn't be understood, she said.

"He was an avid signer as a toddler, but once his speech got better he stopped," she said. Now he and 3-year-old sister Caroline are learning to sign again as Bennett teaches Beatrice.

Bennett uses a combination of online videos and DVDs called Signing Time to teach her children sign language. She's found it's best to teach babies words they're most interested in, such as "eat," "drink" and "more."

"I tried to teach 'diaper,' 'change' and 'potty,' but kids have no interest in those words," she said.

"A lot of people think it's a novelty thing, but I think it's genuinely helpful to make your life easier as parents. It's totally worth the effort, and it can be fun."