A Having survived the ear-piercing screeches of eight little screamers, I have concluded that screaming is a common, yet annoying, stage of infant and toddler development. From the adorable little squeaks and squeals in the early months, to the relentless screams in the later months - it's all a normal part of a baby learning how to talk. Babies begin to experiment with different noises and pitches, usually between five and seven months. By the second half of the first year these noises seem only to get louder and louder.
I believe there are two major reasons why babies and toddlers experiment with these sounds. At first, your baby is amazed at the power and the loudness of his tiny voice. Because it's so new to him, he loves to experiment with different pitches and decibels. Then, he notices the crowd-stopping effects that his powerful outcries have on startled listeners. Nothing gets an adult's attention like the sound of a baby's scream. It's a form of communication that demands the audience listen and respond.
You are probably right to guess that the older, screaming siblings encourage the baby to yell. If your baby is surrounded with other screamers, he's going to scream too. That's because infants are always trying to figure out what sounds get the most attention and what sounds are normal. And for that same reason, you can teach your little one that screaming is not a normal way of communicating. A good first step to a quieter baby is to squelch your two screaming toddlers.
Here are some ways to give your children more socially-acceptable sounds:
Establish a no-scream zone. We used this trick to quiet down Matthew, our loudest toddler: As soon as Matthew started to scream, we'd rush him outside and scream with him. We would then say, "Only scream on the grass." Soon he learned that screaming outside was acceptable, but he was to use his "quiet voice" inside the house.
Don't respond to screaming. Another scream-squelching trick is not to let screaming become a manipulation tool. You want to teach your toddlers that they don't have to scream to communicate their needs. So simply don't respond to it. Walk away, or do whatever you need to do to let them know that screaming will get them nowhere.
Reinforce the "nice voice." Besides teaching them the sounds you won't respond to, teach them the sounds that will get your attention. Try not to act spooked when they scream. Calmly tell them that you will listen to a "nice voice," but not to screaming. Let them know that the "nice voice" is the accepted way that toddlers talk in your family.
Your baby will soon be able to make sounds into intelligible words. He will transfer that fascination with screaming to words and sentences. Usually by two years of age screaming becomes a stage of the past - time is on your side.