thumb|A babbling infant, age 2 months, making cooing sounds
thumb|A babbling infant, age 6 months, making ba and ma sounds
Babbling is a stage in child development and a state in language acquisition during which an infant appears to be experimenting with uttering articulate sounds, but does not yet produce any recognizable words. Babbling begins shortly after birth and progresses through several stages as the infant's repertoire of sounds expands and vocalizations become more speech-like. Infants typically begin to produce recognizable words when they are around 12 months of age, though babbling may continue for some time afterward.
Babbling can be seen as a precursor to language development or simply as vocal experimentation. The physical structures involved in babbling are still being developed in the first year of a child's life. This can be partly attributed to the immaturity of the vocal tract and neuromusculature at this age in life. Infants first begin vocalizing by crying, followed by cooing and then vocal play. These first forms of sound production are the easiest for children to use because they contain natural, reflexive, mostly vowel sounds.
Babbling usually occurs in all children acquiring language. Italian, Korean, French, Spanish,
The sounds produced in babble have been categorised relative to their components. For example, babble may be broken down into syllables that contain a consonant and a vowel (CV syllables) and syllables that contain only a vowel sound (non-CV syllables). These components have been studied in relation to speech development in children, and have been found to relate to future speech outcomes.
If babbling occurs during the first year of life, it can typically be concluded that the child is developing speech normally. As babies grow and change, their vocalizations will change as well.
Timeline of typical vocal development
Infants follow a general timeline of vocal developments in childhood. This timeline provides a general outline of expected developments from birth to age one. Babbling usually lasts 6–9 months in total.
Around 7 months, babies can produce several sounds in one breath, and they also recognize different tones and inflections in other speakers. Variegated babbling differs from reduplicated babbling in terms of the variation and complexity of syllables that are produced. The general structure of the syllables that they are producing is very closely related to the sounds of their native language and this form of babbling significantly predicts the form of early words.
Around 11 months, babies imitate inflections, rhythms, and expressions of speakers. Just as hearing or speaking infants babble with their mouths, infants who grow up with a sign language babble with their hands. produces a number of sounds but only some of them ("ma ma" and "da da", turning into "mommy" and "daddy", respectively) are recognized as meaningful and thus reinforced by caregivers and parents, while the others are abandoned as meaningless (this is the argument in, for instance, Susanne Langer's Philosophy in a New Key). This hypothesis agrees with the claim that the anatomical changes of the vocal tract are very important, but suggests that the social environment in which an infant is raised has a greater influence on the development of language. Infants pay close attention to their caregivers' reactions and use their feedback as approval for the sounds that they are making. This reinforcement through feedback helps infants to focus their attention on specific features of sound. Social feedback facilitates faster learning and earlier production of a variety of advanced words. The babbling drift hypothesis provides further support for The Continuity Hypothesis.
Physiology of babbling
The human mouth moves in distinct ways during speech production. When producing each individual sound out loud, humans use different parts of their mouths, as well as different methods to produce particular sounds. During the beginnings of babbling, infants tend to have greater mouth openings on the right side. This finding suggests that babbling is controlled by the left hemisphere of the brain. The larynx, or voicebox, is originally high in the throat which allows the baby to continue to breathe while swallowing. It descends during the first year of life, allowing the pharynx to develop and facilitates the production of adult-like speech sounds.
Reduplicated babbling (such as 'bababa') involves a rhythmic opening and closing of the jaw. According to the frame dominance theory, when the mandible (jaw) is elevated, a consonant sound will be produced. When the mandible is lowered, a vowel-like sound is produced. Therefore, during a reduplicated sequence of sounds, the consonant and vowels are alternated as the mandible elevates and depresses. The opening and closing of the mouth alone will not produce babbling, and phonation (or voicing) is necessary during the movement in order to create a meaningful sound. Other important oral structures involved in articulation, such as the tongue, lips and teeth remain in a stable resting position during babbling. Sometimes during the babbling period, the motions can be made without any vocalization at all. However, infants with certain medical conditions or developmental delays may exhibit a delay or an absence of babbling. For example, infants who have had a tracheotomy typically do not babble because they are unable to phonate. Following decannulation, it has been found that these infants do produce more vocalizations, but the sounds or syllables are not as diverse as those found in typically developing infant's canonical babbling behaviour. Infants with severe apraxia may not babble, and may fail to produce first words. Communication by infants with apraxia may instead be in the form of grunting and pointing. Babbling may also be delayed in individuals who are born with Down syndrome. The canonical stage may emerge two months later for individuals with Down syndrome compared to other infants, although, when produced, it is similar to babbling in typically developing infants. Babbling should appear if the child is exposed to language, but vocal babbling can be delayed or non-existent for deaf children. This suggests that auditory experience is necessary in spoken language development. Some researchers have taken these findings as evidence against the hypothesis that language is an innate human capability. Many animals produce similar ranges of sounds to human infants. These ranges of sounds are used in the young of many species to experiment with sound-making capabilities, or to practice for future vocal behavior. Similar to human infants, animal babbling is restricted by physiological development.
Songbirds produce varieties of immature songs that are referred to as babbling because the immature songs precede those that are fully developed. As with humans, if these songs are reinforced with positive social feedback, they are more likely to recur. Other conspecifics provide feedback, especially the females in species for which only the males produce song. If females provide more social signals as feedback, males will develop more mature songs at a faster rate than other male birds. Young birds require reinforcement from adults in order to finalize their songs. Another relation to human infants is that the amount of vocalizations is not key, but rather the quality of the sounds that is retained and resembles the final produce of language.
The physiology of the animal is important. The properties of the ear and vocal tract, as well as the brain regions used in analyzing and processing information are critical determinants of how song is interpreted and later produced. In studies using isolated birds that have not had exposure to song, they produce an abnormal 'isolate song' that nevertheless contains species-specific aspects. This shows that the neural pathways have predetermined features that allow for such a phenomenon to occur. The pathways are able to allow for plasticity of the songs that can be learned in the future.
There are a total of 16 call types in pygmy marmoset babbling language. Different calls serve different survival functions such as when desiring food, social interaction or during times of alarm. As human infants have, marmoset babies have higher rates of social interaction when producing babbling sounds. During the juvenile age, marmosets often regress back to babbling stages if a new infant is born. It is suggested that their production of babbling calls increases because they are seeking attention and social interaction. Another babbling occurrence during the juvenile age is the addition of territorial calls and mild threat vocalizations. Although babbling is important for practising adult calls during the juvenile age, babbling decreases with age in pygmy marmosets. Overall, babbling progresses through a series of stages from infancy to adulthood and slowly leads to the construction of adult calls.