Babies learn to communicate with body language before they begin to babble. Eye contact and loving attention from their caregiver as a newborn teaches the infant that they can trust that their cries and needs for food and cleanliness and warmth will be met as well as their need for touch and smiling faces.
Babies are familiar with the sound of their mother's heartbeat and may be familiar with music and language in their environment from an early age. They learn to recognize words and patterns of language long before the ability to speak. Babbling is their way of saying hello and anything else they might be thinking - say hello back or sing along with the babbling. Natural pauses to listen and respond whether with early eye contact and then looking away to later babbling by baby and a response from caregiver is early conversation.
Games like peek-a-boo also teach interaction and that conversation has pauses. It can be natural to speak to infants in a slightly higher pitched voice however they learn normal speech patterns by listening to normal conversation - baby talk is not going to teach language as well as just chatting about what you are doing and labeling things out loud. "Let's get ready for a walk. Putting on baby's coat, and shoes, now for the mittens and hat. Now it's my turn, putting on my coat, and shoes, and my mittens and hat! Now we're ready for a walk!. Won't that be fun?"
Infants who do not have caregivers who respond to the early efforts at communication can leave a baby under-stimulated and they may stop trying. Orphans in overcrowded facilities with little interaction have been found to develop an autism like condition which may be reversed if they receive more nurturing care early enough in life.
"If a baby does not babble, coo or gesture by 12 months, say single words by 16 months or two-word phrases by 24 months, or if there is a loss of language or social skills at any point, he or she should be evaluated by a doctor." - Katherine M. Johnson
Or "Was My Child’s Autism Misdiagnosed?" , by Katherine G Hobbs, AutismParentingMagazine.com.
/Disclaimer: This information is provided for educational purposes within the guidelines of fair use. While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes./