Babbling: Difference between revisions

 

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.<ref name=":3" /> This continued physical development is responsible for some of the changes in abilities and variations of sound babies can produce. Abnormal developments such as certain medical conditions, developmental delays, and hearing impairments may interfere with a child's ability to babble normally. Though there is still disagreement about the uniqueness of [[language]] to humans, babbling is not unique to the human species.<ref name=":5" />

 

Babbling is a stage in language acquisition. Babbles are separated from language because they do not convey meaning or refer to anything specific like words do. Human [[infants]] are not necessarily excited or upset when babbling; they may also babble spontaneously and incessantly when they are emotionally calm.

 

The sounds of babbling are produced before an infant begins to construct recognizable [[words]].<ref name="How do infants attain first signs 4">{{cite journal|last=Takei|first=Waturu|title=How do deaf infants attain first signs?|journal=Developmental Science|year=2001|volume=4|pages=71–78|doi=10.1111/1467-7687.00150}}</ref> This can be partly attributed to the immaturity of the [[vocal tract]] and [[neuromusculature]] at this age in life.<ref name="6 influences">{{cite journal|last=Werker|first=Janet F|author2=Tees, Richard C.|title=Influences on infant speech processing: Toward a new synthesis.|journal=Annual Review of Psychology|year=1999|volume=50|pages=509–535|doi=10.1146/annurev.psych.50.1.509|pmid=10074686}}</ref> 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.

 

 

The [[consonants]] that babbling infants produce tend to be any of the following: {{IPA|/p, b, t, d, k, g, m, n, s, h, w, j/}}. The following consonants tend to be infrequently produced during [[phonological development]]: {{IPA|/f, v, θ, ð, ʃ, tʃ, dʒ, l, r, ŋ/}}. The complexity of the sounds that infants produce makes them difficult to categorize, but the above rules tend to hold true regardless of the language to which children are exposed.<ref>{{Cite book|title=Contemporary linguistic analysis: An Introduction|editor1-last=O'Grady |editor1-first=W. |editor2-last=Archibald |editor2-first=J. |name-list-style=amp|publisher=Pearson|year=2011|isbn=9781256320258|location=Boston}}</ref>

 

 

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.<ref name=":1">{{Cite book|title = Language Development: An Introduction|url = https://archive.org/details/languagedevelopm0000owen|url-access = registration|last = Owens|first = R. E.|publisher = Pearson|year = 2005|location = Boston|pages = [https://archive.org/details/languagedevelopm0000owen/page/125 125]–136}}</ref> This timeline provides a general outline of expected developments from birth to age one. Babbling usually lasts 6–9 months in total.<ref name=":5" /> The babbling period ends at around 12 months because it is the age when first words usually occur. However, individual children can show large variability, and this timeline is only a guideline.

 

 

=== Manual babbling ===

[[Manual babbling]] is structurally identical to vocal babbling in its development.<ref name="Petitto">{{cite journal |last1=Petitto |first1=L. |last2=Marentette |first2=P. |title=Babbling in the manual mode: evidence for the ontogeny of language |journal=Science |date=22 March 1991 |volume=251 |issue=5000 |pages=1493–1496 |doi=10.1126/science.2006424 |pmid=2006424 |bibcode=1991Sci...251.1493P |s2cid=9812277 }}</ref> Just as hearing and/or speaking infants babble with their mouths, infants who grow up with a [[sign language]] babble with their hands.<ref name="Petitto" /> If a hearing infant has deaf and/or mute parents or parents who otherwise use a sign language, they will still imitate the signs that they see their parents displaying. This is evidence that manual babbling is possible in both hearing and deaf infants, and in both speaking and mute infants.<ref name="Petitto" />

 

Children are able to produce signs correctly, which is important since many articulation tendencies of manual babbling transfer to the children’s early sign production.<ref name="Cheek" /> Children acquire signs for the same concepts as speaking children's words, and in the same stage of development.<ref name="Cheek" />

 

Two hypotheses have been devised in order to explain how babbling is related to language development.<ref name=":5" />

 

*'''Continuity hypothesis''' – According to this hypothesis, babbling is a direct forerunner to language. At first, infants produce universal sounds that exist in all areas of the world and in all languages. Reduplicated canonical babbling<ref name="Role audition 3 babbling page">{{cite journal|last1=Oller|first1=D. Kimbrough|last2=Eilers |first2=Rebecca E.|title=The Role of Audition in Infant Babbling|journal=Child Development|year=1988|volume=59|issue=2|pages=441–449|doi=10.2307/1130323|jstor=1130323|pmid=3359864}}</ref> 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]]'').<ref>{{cite journal|last=Bryan|first=Alan Lyle|year=1963|title=The Essential Morphological Basis for Human Culture|journal=[[Current Anthropology]]|volume=4|issue=3|pages=297–306|jstor=2739612|doi=10.1086/200377|s2cid=145615606}}</ref> 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.<ref name="Social Feedback 7" /> There is evidence that babbling varies depending on the linguistic environment in which a baby is raised. Current babbling research supports The Continuity Hypothesis. For example, it has been noted that infants raised in French speaking environments display greater amounts of rising intonation in comparison to infants raised in English speaking environments. This is likely due to the differences between French and English intonations while speaking. The ordering of consonants and vowels in the babbling of English, French, Swedish and Japanese infants also appears to resemble that of their native language. These findings support another hypothesis, the "babbling drift hypothesis" in which infant babbling resembles the phonetic characteristics of a child's native language through exposure to speech. When babies are exposed to two languages, their babbles resemble the language that they are most exposed to. The dominant language is considered to be the one that children have the most exposure to. Most often infants do not produce a blend of language styles while babbling however, may switch between languages. Sometimes infants may choose which language style they prefer to babble in based upon particular features.<ref name="10 Language diff in bilingual">{{Cite book |doi = 10.1075/tilar.1.06pou|chapter = Language differentiation in bilingual infants|title = Trends in Bilingual Acquisition|volume = 1|pages = 95–106|series = Trends in Language Acquisition Research|year = 2001|last1 = Poulin-Dubois|first1 = Diane|last2 = Goodz|first2 = Naomi|isbn = 978-90-272-3471-1}}</ref> The babbling drift hypothesis provides further support for The Continuity Hypothesis.

 

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.<ref>{{Cite journal|last1=Holowka |first1=S. |last2=Petitto |first2=L. A. |name-list-style=amp|date=2002|title=Left hemisphere cerebral specialization for babies while babbling|journal=Science |volume=297 |issue=5586 |page=1515 |doi=10.1126/science.1074941|pmid=12202820|s2cid=35314696 }}</ref> 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.<ref name=":3">{{cite book |first=Naomi S. |last=Baron |title=Growing up with Language: How Children Learn to Talk |location=Reading, Massachusetts |publisher=Addison-Wesley |year=1992 |pages=41–43 |isbn=0-201-55080-6}}</ref>

 

 

== Abnormal development ==

Typically by 6 months of age, all normally developing children will babble.<ref>{{Cite book|title = Encyclopedia of Human Development|url = https://archive.org/details/encyclopediahuma00salk|url-access = limited|last = Salkind|first = N. J.|publisher = Sage |year = 2006|location = Thousand Oaks, California|pages = [https://archive.org/details/encyclopediahuma00salk/page/n189 151]|isbn = 9781412904759}}</ref> 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.<ref name=":0">{{Cite book|title = Encyclopedia of Human Development|url = https://archive.org/details/encyclopediahuma00salk|url-access = limited|last = Salkind|first = N. J.|publisher = Sage |year = 2006|location = Thousand Oaks, California|pages = [https://archive.org/details/encyclopediahuma00salk/page/n190 152]|isbn = 9781412904759}}</ref> 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.<ref>{{Cite journal|title = Babbling and early speech: continuity and individual differences|last = Locke|first = J. L.|date = 1989|journal = First Language|volume = 9|issue = 6|pages = 191–205|doi = 10.1177/014272378900900606|s2cid = 145364002}}</ref> Infants with severe [[Apraxia of speech|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.<ref name=":0" /> Infants with [[Autism spectrum|autism]] may show a delay in babbling, and in some cases it may be completely absent.<ref name=":0" /> Babbling in children with autism tends to occur less frequently than in typically developing children, and with a smaller range of syllables produced during the canonical babbling stage.<ref>{{Cite journal|title = Vocal Patterns in Infants with Autism Spectrum Disorder: Canonical Babbling Status and Vocalization Frequency|journal = Journal of Autism and Developmental Disorders|date = 2014-01-31|issn = 0162-3257|pmc = 4117826|pmid = 24482292|pages = 2413–2428|volume = 44|issue = 10|doi = 10.1007/s10803-014-2047-4|first1 = Elena|last1 = Patten|first2 = Katie|last2 = Belardi|first3 = Grace T.|last3 = Baranek|first4 = Linda R.|last4 = Watson|first5 = Jeffrey D.|last5 = Labban|first6 = D. Kimbrough|last6 = Oller}}</ref> 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.<ref name=":0" />

 

 

Research has been conducted to determine whether or not infants with impaired hearing can demonstrate typical vocal sounds. Babbling can appear at the same age and in similar forms in hearing and deaf child, however, further continuation of babbling and speech development depends upon the ability for the child to hear themselves. For this reason, deaf children stop babbling vocally earlier than hearing children.<ref>{{Cite journal|title = Babbling and the deaf child: a commentary on Lenneberg et al. (1965) and Lenneberg (1967)|journal = Journal of Child Language|date = 1982-06-01|issn = 1469-7602|pages = 511–515|volume = 9|issue = 2|doi = 10.1017/S0305000900004840|pmid = 7119048|first = John H. V.|last = Gilbert| s2cid=38338506 }}</ref> Babbling should appear if the child is exposed to language, but vocal babbling can be delayed or non-existent for deaf children.<ref name="Cheek" /> It is not clear whether spoken language can develop fully without auditory experience.<ref name="Role audition 3 babbling page" /> Deaf children are not only significantly delayed in spoken language development in comparison to their hearing counterparts, but they also produce fewer noises.<ref name="5 rel of aud">{{cite journal|last=Bass-Ringdahl|first=Sandie M.|year=2010|title=The Relationship of Audibility and the Development of Canonical Babbling in Young Children With Hearing Impairment|journal=Journal of Deaf Studies and Deaf Education|volume=15|issue=3|pages=287–310|doi=10.1093/deafed/enq013|pmid=20457674|pmc=2912640}}</ref> 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 [[Innateness hypothesis|innate human capability]].<ref name="3 co-occurence" />

A number of solutions have been used for hearing-impaired humans to gain auditory experience, one of which is [[hearing aids]]; they can be used to help infants reach babbling stages earlier.<ref name="Role audition 3 babbling page" /> [[Cochlear implants]] have also been tested. Once the surgical implantation is complete, an infant has the opportunity to experience spoken language input. Once language has been heard, the infant begins to babble and speak in rhythmic patterns just as hearing infants do.<ref name="3 co-occurence" />

 

Though there is disagreement about the uniqueness of [[language]] to humans, babbling is not unique to the human species.<ref name=":5">{{Cite book|title = The Psychology of Language 2Ed|last = Harley|first = Trevor|publisher = Psychology Press|year = 2001|isbn = 978-0-86377-867-4|location = New York|url-access = registration|url = https://archive.org/details/psychologyoflang0000harl_q7q3}}</ref> 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.<ref name=":4" />

 

Not only are [[songbird]] and human language parallel regarding neural and molecular factors, they also are similar in how their communication is initially produced. Observations about these similarities can be traced back to [[Charles Darwin]] and his studies. [[Bird|Avian]] and [[mammalian]] brains are similar in form and connectivity and there may even be a [[gene]] that is relevant to speech found in both organisms. The learning of a song is produced through a mix of interaction, experience, and predisposition. Young songbirds will imitate their species' call when presented with songs from their own and another species. They are physically capable of producing either song, but do not. Humans learn language through similar means, which is why this early vocalization in songbirds is considered babbling.<ref name=Bolhuis>{{cite journal|last1=Bolhuis|first1=J. J.|last2=Okanoya |first2=K. |last3=Scharff |first3=C. |title=Twitter evolution: Converging mechanisms in birdsong and human speech|journal=Nature Reviews Neuroscience|year=2010|volume=11|issue=11|pages=747–759|doi=10.1038/nrn2931|pmid=20959859|s2cid=924972}}</ref>

 

There is an important phase in development when song learning is best accomplished. This phase is called the 'sensitive period' and the amount of change that a songbird experiences in adulthood varies by species. Young birds have a production phase after a listening phase of development. The production of song is called 'subsong' where vocalizations resemble that of an adult as time passes. Memory for songs is able to form before the period where learning to sing occurs. Social interaction is important in vocal learning where non-singing females can even influence an infant through feedback.<ref name=Bolhuis />

 

 

[[Pygmy marmoset]]s have been studied and found to produce complex vocalizations 2–3 weeks after birth. Both sexes are capable of creating calls at a rate of 3 calls/second and each bout of calls can last up to 6 or 7 minutes. A normal series of calls by a pygmy marmoset contains approximately 10 different call types. This variety of call forms produced by this creature is comparable to babbling in human infants for a number of reasons. Like reduplicative babbling in humans, the call is often repeated several times before a new sequence of sounds is produced. The vocalizations gain attention from caregivers and provide practice for future vocal behavior. For these reasons, pygmy marmoset calls are seen as babbling behavior.<ref name=Snowdon>{{cite journal|last1=Snowdon|first1=C. T.|last2=Elowson |first2=A. M.|title='Babbling' in pygmy marmosets: Development after infancy|journal=Behaviour|year=2001|volume=138|issue=10|pages=1235–1248|doi=10.1163/15685390152822193}}</ref>

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.<ref name=Snowdon />

 

Babbling-like behavior in songbirds, humans and some nonhuman primates has been previously researched, but it has not been researched until recently in non-primate mammals. The [[sac-winged bat]] (''Saccopteryx bilineata'') is a social creature and the vocalizations that it produces depend on the social situation that the animal is in. This bat has a large repertoire of vocalizations with males being more vocal than females. [[Animal echolocation|Echolocation]] pulses, barks, chatters, and screeches are used in various social situations including courtship and territorial defense. Infants produce isolation calls if their mothers are absent, but the pups also produce vocalizations that mirror those of adults. Both sexes of infants babble, even though as an adult, the vocalizations are solely produced by males. Social context, mothers, and surrounding bats do not influence pups because the multiple vocalizations are combined regardless of the situation. Since there is not a social aspect correlated with the vocalizations, the productions of the sounds suggest that the pups vocalize for training. The pups repeat and combine adult vocalizations so that they resemble babbling in what humans, other primates and some songbirds do as infants. However, while human babbling increases social interactions, there are no social responses to babbling in bats. Babbling is common in infants that have a large repertoire of adult vocalizations to learn and this is seen in the pups of sac-winged bat.<ref>{{cite journal|last1=Knornschild|first1=M. |last2=Behr |first2=O. |last3=Von Helversen |first3=O.|title=Babbling behavior in the sac-winged bat (Saccopteryx bilineata)|journal=Naturwissenschaften|year=2006|volume=93|issue=9 |pages=451–454|doi=10.1007/s00114-006-0127-9|pmid=16736178|bibcode=2006NW.....93..451K |s2cid=33556162 }}</ref>