The child is also more able to raise and lower the jaw. A lower jaw also lowers the tongue, creating the possibility of more vowels. Raising the jaw allows for more lip and tongue tip constrictions.

Source: http://sapir.ling.yale.edu/ling165/

1. Repetitive babbling - same syllable in each successive cycle
2. Variegated babbling - variation in syllables in successive cycles

Text from http://sapir.ling.yale.edu/ling165/

Essentially, all children use the same sounds when they babble, no matter what the language around them is. "The consonants that occur with substantial frequency in the babbling of infants, regardless of language environment (Locke, 1983) are:

/b/ /d/ /g/ /p/ /t/ /k/ /m/ /n/ /w/ /j/ /h/

Vowels in babbled syllables tend to be low front:" /æ/ "or central:" /a/.

The universality of babbling makes sense when you realize that the easiest way to make a sound is to simply open and close the mouth. It is not surprising that stops will be highly prevalent in the inventory since they are produced by closing the oral cavity, which happens when closing the mouth occurs. The rest of the difference between the stops is where in the mouth the tongue contacts the other parts of the vocal tract. For example, depending on whether a child rests the tongue on the bottom of the mouth behind the lower teeth or whether it rests in the middle just behind the front teeth accounts for the difference in the production of bilabial and alveolar sounds in babbling. All the child has to do is open and close the mouth, and different sounds will be made.

Think of the words (we'll use English here) that we use to refer to many baby items and caretakers:

• Baba (bottle)
• Mama (mother)
• Nana (grandmother)
• Papa (father)
• Dada (daddy)

• Bubu (hurt)
• Mumu
• Nunu
• Pupu (poopoo)
• Dudu (doodoo)

• Mami (mommy)
• Papi (Poppy, often used for grandfather)
• Pupi (poopy)

And we’re back to Baby Talk. Baby talk has two different meanings:

1. It is the way that babies themselves talk, and when baby talk is used with this meaning, it refers in particular to the babbling stage and the first words stage of language acquisition, universal stages for all infants in all languages.
2. It is the way that adults talk when they talk to babies. When baby talk is used with this meaning, it captures the fact that adults accommodate their speaking style to that of the child. They help the child attach meaning to their utterances by using the same utterances with the meaning attached.

In other words, deaf children babble in sign language and just make noises with their mouths. Hearing children babble with their mouths, and just make gestures with their hands. For hearing children, language is produced with the mouth, and extralinguistic communication with the hands. For deaf children, language is produced with the hands and extralinguistic communication with the mouth.

During the Babbling Stage infants begin to ignore/lose the ability to distinguish between the sounds of their parents’ (caretakers’) language and other sounds.

They respond only to sounds that are the language distinctions of their parents’ (caretakers’) language.

In other words, prelinguistic Korean infants respond to the difference between [l] and [r]; children in Arabic environments do the same with [p] and [b]; children in Spanish environments the same with [i] and [I]. But in the babbling stage, they no longer respond to the difference, treating both sounds the same.

Remember that this starts at about 6 months of age; the early disappearance of awareness of phonetic distinctions has great implications for second language learning and pronunciation and lends support to the critical period hypothesis for first language acquisition.