Baby sign language

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Baby sign language, pioneered by Dr. Joseph Garcia, is the use of manual signing in order to communicate with infants and toddlers. While infants and toddlers have a desire to communicate their needs and wishes, they lack the ability to do so clearly because the production of speech lags behind cognitive ability in the first years of life.[1] Proponents of baby sign language say this gap between desire to communicate and ability often leads to frustration and tantrums.[2][3] However, since hand-eye coordination develops sooner than acquisition of verbal skills, infants can learn simple signs for common words such as "eat", "sleep", "more", "hug", "play", "cookie", and "teddy bear" before they are able to produce understandable speech.[4][medical citation needed] Each individual infant will develop the ability to sign at a slightly varied stages in his or her growth. Before the infant will be able to sign it is necessary for the infant to be able to focus on the hand movement and have the cognitive skill to link a certain gesture to an item resulting in why babies will begin signing at various ages.[5]

Differentiating Baby Sign Language[edit]

What is Baby Sign Language?[edit]

Baby sign language involves both individual and commercialized signs that infants learn with the intention of creating richer parent- child communication. The main purpose of implementing baby sign language is to reduce the frustration involved in trying to understand what the child is communicating. It can be considered a useful method of communication in their early developmental stages since speech production follows the infant's cognitive ability to express themselves through bodily movement.[6]

To avoid any misconceptions it is important to understand that baby sign language and American Sign Language (ASL) are distinctive methods of manual communication. ASL is a standardized communicative approach within the deaf community that has gained interest in baby sign programs.[6] ASL is much more complex to teach infants because it maintains the same linguistic properties as spoken language.[7] Teaching baby signs on the other hand allows for greater flexibility by not being required to learn the precise ASL system.[6] Baby signs are rather modified ASL signs or are completely individualized signs that are likely easier for the infant to form. Both All- ASL and baby- friendly approaches have been taught in baby sign training programs though it is the parents preference as to which method to adhere to.[6]

It is also common for the clear difference between symbolic gestures and baby sign language to be mistaken. Symbolic gestures is the typical way that children communicate before they obtain the ability to produce spoken language. Such methods as pointing to what they want or using a hand motion in conjunction with a word allows greater communication for infants. Typically developing children will produce their first gestures between the ages of 9 and 12 months without any prompting or assistance from a caregiver. Infants learn how to use their body language, eye gaze, and hand gestures as a way to attract attention and communicate. Once children gain some language production they will couple language with gesture to further communicate their point.[8] Gesture remains present in all individuals at any age which is a distinguishing factor from baby sign.

Supportive Research[edit]

In an article in the British Psychological Society's The Psychologist[9] Gwyneth Doherty-Sneddon has considered in detail the theoretical basis behind the growth of this phenomenon and some of the claims made by its supporters.[10] As Doherty-Sneddon points out, so-called "baby signing" is not entirely new. Variants have been used by speech and language therapists for decades with children who have impairments to their speech, their cognitive abilities, or both.[11] It is widely recognized that communication is at the heart of child development, be it cognitive, social, emotional or behavioral.[12]

Dr. Joseph Garcia along with Drs. Linda Acredolo and Susan Goodwyn along with others produced separate works around the same time period that greatly influenced the baby sign language movement. Dr. Joseph Garcia's first book Toddler Talk was published in 1994 following his graduate research. His research indicated that babies who are exposed to signing regularly and consistently at six to seven months can sign effectively within two to three months.[13] It was the first book to appear on the market regarding baby signing. In 1999, he published Signing With Your Baby, which became an best-seller winning numerous awards. Acredolo and Goodwyn are well known for their several further research studies as well as their more recent book Baby Signs: How to Talk with Your Baby Before Your Baby Can Talk which was published in 2009, all intending to demonstrate support of baby sign.

A popular study led by Drs. Linda Acredolo and Susan Goodwyn studied 11-month-old children who up until the age of three their speech and language development was monitored. The children were assigned to three groups in this study: the first group consisted of children that were taught words including concurrent symbolic gesturing; a second group consisted of children whose parents stressed verbal training and taught the same words; and a third group received no special emphasis on training. In order to develop baby signs from symbolic gesturing the experimental group had to go beyond typical contextual cues. Results showed that the average scores of children in the study that were in the group that used baby sign language were found to be higher than the non-training control group. No direct comparison was made between the symbolic gesture training group and the verbal training control group. By the age of 36 months, there was no continued advantage in the group that had been taught by symbolic gestures when compared to the non-trained control group.[14][15]

They conclude the study by suggesting that it is not signing alone that enhances further language development but rather it is facilitated by the encouraged vocalization and contingent interaction between the parent and child. Baby signs evoke the attention of the parent and child leading to further elaboration of what the infant is communicating which leads to greater language development by exposure. Therefore an increased number of joint visual attention during parent- child interaction empowers the infant to focus the topic and context of the conversation, clarify concepts, and creates added practice with symbolic interaction.[14] These underlying mechanisms of baby sign are proposed to create benefits for the infant such as; enhance vocabulary, advance cognitive development, reduce tantrums and frustration, improve the parent- child relationship and communication. More specifically language development is enhanced by advancing comprehension, and promotes literacy and the fact that it successfully allows the infant to express their needs the parent becomes more responsive and observant of their baby.[16][14]

Mueller and Sepulveda gained self reports from mothers who engaged in a baby sign training workshop to clarify whether or not signing with their child reduced parental stress and enhanced parent- child communication. Following the workshop the responses of the parents tended to be mainly positive due to the helpful assistance of researchers throughout the process. Overall the parents reported a reduced stress level or frustration due to an enhanced ability to understand their child. This richer communication was stated to also lead to a more positive interaction with their child which overall increased their bond.[17]

Another study, involving two hearing impaired baby boys, looked at the significance of when baby sign language is introduced to a child. One boy's hearing loss was determined shortly after birth, and began learning baby sign language very early. The second boy was not determined to have hearing loss until he was two years old, and therefore was not exposed to baby sign language until then. The results of this study showed that the boy who was taught baby sign language had better acquisition of overall language skills, while the other boy, who was taught verbal language until his hearing impairment was detected, had a much more difficult time with language skills.[18] Baby sign language can prove to be crucial towards language development in some cases, yet does not cause any harm to those who do not have hearing impairments.

According to Karen Emmorey, research has concluded that children develop language skills around the same time, regardless of being taught verbal or sign language. However, it appears that children who learn sign language begin manual "babbling" with gestures earlier than the spoken babbles of a baby exposed to verbal language.[19] Baby sign language promotes communication before a child is able to verbally communicate with others. Since hand-eye coordination develops earlier than a child's ability to speak verbally, baby sign language allows a baby to begin experiencing and developing his or her language skills before he or she is physically able to speak.[20][21][6] Since gestures are part of normal speech, teaching baby sign language allows babies to learn an aspect of communication that is used to replace verbal language.[22][8] The advantage is that babies are able to learn gestures before verbal skills, and therefore those who learn ASL and some related baby signs may enhance their cognitive development by acquiring language skills through both visual and auditory modes.[23]

Developmental research[edit]

Research by Bonvillian & Folven indicates that children raised in a signing environment produce their first signs at a mean age of 8.2 months, whereas Capute et al. found a mean age of 11.3 months for the production of the first word in speaking children. This acquisition advantage has been found to extend to multi-word and multi-sign milestones as well. Signing children acquired 10 sign vocabularies at a mean age of 13.1 months, compared with 10-word vocabularies at a mean age of 15.1 months for speaking children. Milestones of 50 signs and 50 words were acquired at mean ages of 18 months and 19.6 months respectively.[24][25]

Two-sign combinations were first produced at a mean age of 17.1 months, while two-word combinations were first produced between 18 and 24 months. Acquisition of morphology or inflection was not found to differ greatly between signing and speaking children.[26]

In 1998, a program was conducted at A. Sophie Rogers Infant-Toddler Laboratory School in Ohio State University by Kimberlee Whaley. Infants as young as 9 months old and their teachers began to learn to use some signs from the American Sign Language to communicate with each other. The program was not intended to teach American Sign Language, rather to use signs to communicate effectively. The program found that children would use the signs they learned in the classroom at home. Another finding indicated that girls use signs more than boys.[27]

Volterra et al. (2006) [28] conclude enhanced gesture input for hearing children is a catalyst for gesture acquisition, and especially the use of representational form and hence symbolic communicative function. They add that this enhancement is short-lived (to between 12 and 15 months of age). Doherty-Sneddon argues, however, that this timescale represents only a general norm. The enhancement and advantage is far more extended in the many toddlers who do not speak until well after their second birthdays. Doherty-Sneddon concludes by arguing there are three different levels of support for the benefits of baby signing of which include; indicative evidence from baby signing research, related evidence from deaf sign and hearing gesture/language research, and compelling anecdotal support from families who have embraced the approach.

Doherty-Sneddon also claims a key issue is ensuring that sufficient and appropriately designed research is available to back the claims made in relation to baby signing. A literature review concluded that although benefits were reported in 13 of 17 studies, various methodological weaknesses leave the evidence unconfirmed.[29] Certainly, research into the effects of baby signing needs better control groups, such as children who are involved in equally interesting and fun activities based around adult and child language interaction, but not baby signing.

Contrasting Research[edit]

Baby sign programs encourage mothers to improve their communication skills between themselves and their preverbal infants.[30] Kirk et al. (2013) have found that the results of their study with healthy infants provided no evidence to support that through learning baby sign, a child's language development would be benefitted. They also found that children who participated in baby sign had similar language development as children who did not partake in learning baby sign. It is suggested that participating in baby sign may be an unnecessary effort with infants when being motivated by the hopes of advanced linguistic outcomes in the child. However, it was found that mothers who used baby sign with their infants encouraged increased independence with them and supported a higher level of autonomy with their child.[30] Another conducted research study has shown that there are no significant differences found with language acquisition, including reaching linguistic milestones, between infants who are receiving or not receiving exposure to baby sign.[31] Although no support for using baby sign was found in this study, there was also no negative effects found to be associated with language development when using baby sign. It is possible that baby sign is working in support of infant vocalization, but was not found to facilitate their later spoken development.[31]

The results of multiple studies regarding baby sign have found that linguistic advantage does not proceed children over the age of two years old.[32] The results of this literature review have not shown support that baby sign increases a child's linguistic development. When training a child in baby sign, an infants attention is directed away from what they are interested in and is redirected towards the adult and the desired sign. This interaction has been claimed to increase joint attention between parent and child, but has yet to be studied adequately in research literature.[32] It has also been suggested that baby sign may increase parental stress rather than decrease it because of busy lifestyles disrupting interactions between parents and children. Teaching baby sign in the absence of researchers where the parent does not have the opportunity to raise questions or concerns in contrast with Mueller and Supulveda's study may heighten stress levels.[17] Reaching fundamental linguistic milestones and the natural course of children's development has been suggested to be disrupted because of the unnatural intervention in language development that baby sign provides.[32] It is argued that baby sign may compete with spoken language in children partaking in it as it may cause cognitive overload for the child.


Researchers have suggested the possibility of parents and experimenters being overly liberal in attributing sign or word status to early attempts at communication by children.[33] There is not a universal consensus on the criteria for differentiating a child's sign or word from a more simple gesture or vocalization. Large differences in acquisition arise when only signs that label objects rather than request objects are considered. In this case the mean age of first sign production becomes 12.6 months and is more comparable with the mean age of first word production in speaking children (11.3 months).[24]

Children sometimes produce a combination of a pointing gesture and a spoken word earlier than they would produce a spoken two-word combination.[34] As not all studies are uniform in accepting or disqualifying pointing gestures as signs, this can also lead to discrepancies depending on how the research is carried out.

Additionally, two possible explanations have been suggested for the differences shown in language acquisition between speaking and signing children.[35]

Multiple Timing Mechanism
Under this theory, separate developmental mechanisms would control vocabulary and syntax development. Earlier maturation of the visual system as compared with the oral system would result in the first sign being easier to produce versus the first word. This would also allow for the separate development of vocabulary and syntax.
Unitary Timing Mechanism
This developmental mechanism would be activated at the start of language learning and would result in a relatively fixed amount of time between language acquisition milestones. Alternatively, a unitary mechanism could activate at the same time in all children, irrespective of the onset of language learning. Environmental or peripheral factors, such as language modality or differences in a language's morphology and syntax could explain the differences between acquisition milestones in speaking and signing children.

The Practice of Learning Baby Sign[edit]

Parents and caregivers can sign to babies beginning at birth (using signs for simple ideas like "milk" and "more"). Comprehension on the part of the baby can begin at six months, and the children can begin producing signs themselves around 10 months. Parents and caregivers should be aware that infants will recognize their first sign before producing their own. They should also be patient with their children when they first begin signing to their children because it may take a little while before the baby can understand or even produce signs themselves.Consistency is crucial when teaching your infant how to sign. Infants learn through repetition - that is why it is essential for parents and caregivers to repeatedly use signs. Every time an action is performed the caregiver should sign the action to the child. When using a sign the parent should say the word out loud because this will help the baby link the gestures to verbal skill development.[36]

There have been studies to show that, even by increasing the use of gesture, not necessarily use of a sign language (such as ASL) can increase the richness of a child's linguistic development and speed future processing.[37] It is suggested that learning signs happens over a period of time and it is important to be patient with children and learning baby sign does not happen during a brief interaction between a parent and child.[38] Children show individual variation while undergoing development, and it is crucial to remember that there is considerable variation between different children and how quickly they learn to baby sign.

Advanced Gesture through Interaction with Parent[37] Goodwyn, Acredolo & Brown (2000) have investigated the effects of instructing parents to encourage gesture use on language development. There were three groups studied. The "gestural training group" parents were given a set of 8 toys and told what gestures would be used with each toy. They were also encouraged to create gestures or use isolated ASL signs with their children; parents were presumably not native signers. Both the experimental and control groups were given receptive and expressive tests at 11, 15, 19, 24, 30 and 36 months. Receptive language means being able to recognize words and signs while expressive language means being able to form words or signs. The study found that children whose parents taught them symbolic gestures performed better on both expressive and receptive verbal language tests than children who had not been encouraged to learn such gestures.The results of these tests proved that children who were introduced to symbolic gestures had advance verbal development.[39]

The most interesting point seems to be that the Gestural Training Group may have small but reliable advantages in early language milestones other than age of the first word:

  • "enhanced symbolic gesturing seemed to benefit Gesture Training infants' receptive and expressive language development."
  • The evidence helps to alleviate previous notions that gesture or sign language might interfere with or slow down language development.

A naturalistic case study that was done in Central Texas focused on ideologies and socialization of baby sign language. This study had 3 families that participated. This study was performed through naturalistic interactions that took place in each of the families home. They were videotaped during meal and play time for a total of 7 hours. These ideologies value early communication with infants and promote the adaptation of the physical, social, and linguistic environment to their perceived needs. In this study it showed that baby-signing families used signs to socialize their children into particular interaction rituals.[40]

Case study on bilingual exposure[edit]

A study entitled "Hearing Children Exposed to Spoken & Signed Input"[37][41][42] investigated the transition from gesture to sign in a case study of an Italian, hearing, bimodal, bilingual child.

Marco was "a bilingual hearing child of deaf parents exposed to sign and [oral] language from birth". Though both parents were deaf, they used both Italian Sign Language (LIS) and spoken Italian, at some times simultaneously. Marco was also regularly enrolled in a day care with Italian-speaking peers.

Gesture was considered anything that a hearing (Italian) monolingual child had also been observed producing, whereas LIS was only considered in use if it resembled an adult speaker's LIS or a simplified sign, as judged by a native signer.

The study noted these points as interesting:

  • Under these criteria, Marco did not appear to have a "sign advantage." "Sign advantage" refers to the hypothesis that children who learn sign language and spoken language simultaneously will reach early linguistic milestones more rapidly in sign than in speech.
  • Differences appeared in Marco's use of deictic and representational gestures as compared to those of monolingual children.
  • "While Marco used proportionately more representational than deictic gestures at both comparison points, monolingual children produced deictic gestures much more frequently than representational gestures."
  • He was able to use representational gestures more comfortably and practically, showing that "exposure to sign language may enhance a children's appreciation of the representational potential of the manual modality; this may, in turn, generalize to gesture use."
  • Marco differed from all the studied monolingual peers in that he was able to combine and use two representational gestures.

Media and Internet Influence[edit]

Baby sign language was a plot element in the movie Meet the Fockers, where Jack (Robert De Niro's character) had taught his grandson "Little Jack" sign language. The twins that portrayed Little Jack (Bradley and Spencer Pickren) learned sign language from watching Signing Time! videos.[43]

Due to the portrayal of baby sign in movies, along with other representations in popular culture, parents attempts at signing with their baby may be more focused on the social fad over the intention of potentially enhancing their child's communication skills.[44] Regardless of the reason a caregiver chooses to implement baby sign language they must have access to reliable sources explaining what baby sign is, how to use it, and if there are any benefits associated with it.

When looking for information on baby sign, the internet is one easily accessible avenue with a multitude of information. With access to large ports of information however, it can be difficult to determine what is reliable and what is not. A study conducted by Nelson, White, and Grewe in 2012 identified baby sign websites by typing the search terms ‘baby’, ‘sign language’, ‘infant’, and ‘gesture’ into the google search engine. Results found thirty-three websites that all promoted baby sign language and the benefits associated. When the website sources were examined it was found that over 90% of the information was referring to opinion articles or promotional products encouraging parents to sign, with little to no evidence of real research. This demonstrates that although the websites claim that using baby sign will reduce tantrums, increase infant’s self-esteem, satisfaction, and accomplishment, increase parent-child bonding, and decrease frustration, the sites do not provide ample amounts of research based evidence to support these claims.[45] 

A similar study was conducted by Fitzpatrick, Thibert, Grandpierre, and Johnston in 2014. Websites evaluated in this study were found using the google scholar search engine as well as a few academic databases. The question Fitzpatrick and colleagues were looking to answer, solely through use of material cited on the websites, was: does baby sign encourage developmental, social, cognitive, and language skills while promoting a greater bond between parent and child?[46] The goal of asking this question was to find information that will allow parents, caregivers, childhood educators, and clinicians to make informed decisions about the amount of emphasis to place on baby sign. When all the cited material was gathered there were 1747 articles with only 10 articles providing adequate research depicting outcomes of baby sign language.[46] Consensus gathered from these 10 articles states that baby sign, as used by the commercially advertised product authored by Acredolo and Goodwyn, does not benefit language production or parent-child relationships. However, there is also no evidence from these articles that baby sign is in any way harmful to infants.[46] Through these two studies it is illustrated that websites may not contain 100% research based information. Therefore individuals looking for information regarding the pros and cons of using baby sign should ensure they are accessing sites backed by research and not opinion.

Promotional Material[edit]

Products and training received by parents participating in baby sign in research studies has not been found to be comparable to the quality of products available commercially to parents.[32] It is suggested that parents are cautious of baby sign products as it is difficult to tell the credibility of commercialized products for facilitating baby sign with your child.[32]


See also[edit]


  1. ^ Loncke, F., Bonvillian, J. & Dooley, T. "in preparations- Applications of the Simplified Sign System". 2012.
  2. ^ Garcia, Joseph. "Baby Sign Language Research." Sign2Me. Northlight Communications, Inc., 2010. Web. 23 Sep 2010. <>.
  3. ^ Summary of the Benefits of Signing. Signing Time! Two Little Hands Productions, 2006. Web. 23 Sep 2010. <>.
  4. ^ "Benefits for Babies Using Baby Sign Language". Archived from the original on 7 April 2007. Retrieved 27 March 2007. 
  5. ^ Cesafsky M. J. (2009). Baby Sign Language: Hindering or Enhancing Communication in Infants and Toddlers? 1–29. Retrieved from 2009/2009cesafskym.pdf
  6. ^ a b c d e Acredolo & Goodwyn, L. & S. (2009). Baby Signs: How to Talk with Your Baby Before Your Baby Can Talk. New York: McGraw Hill. 
  7. ^ Capone & McGregor, N. C. & K. K. (2004). "Gesture development: A review for clinical and research practices". Journal of Speech Language and Hearing Practices. 
  8. ^ a b Iverson & Goldin- Meadow, J. M. & S. (2005). "Gesture Paves the Way for Early Language Development". 
  9. ^ "The great baby signing debate". The British Psychological Society. 3 April 2008. Archived from the original on 12 July 2010. Retrieved 19 July 2010. 
  10. ^ Doherty-Sneddon, G., "The great baby signing debate", The Psychologist, Vol. 21, Part 4, April 2008, pp300-303
  11. ^ Clibbens, J., Powell, G.G. & Atkinson, E. (2002). Strategies for achieving joint attention when signing to children with Down's syndrome. International Journal of Language and Communication Disorders, 37(3), 309–323
  12. ^ Vygotsky, L.S. (1978). Mind in society. Cambridge, MA: Harvard University Press
  13. ^ "Dr. Joseph Garcia". Stratton/Kehl Publications, Inc. Retrieved 19 March 2008. 
  14. ^ a b c Goodwyn, S., Acredolo, L. & Brown, C.A. (2000). Impact of symbolic gesturing on early language development. Journal of Nonverbal Behavior, 24, 81–103
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  16. ^ Acredolo, L.P., Goodwyn, S.W., Horobin, K. & Emmons, Y. (1999). The signs and sounds of early language development. In L. Balter & C. Tamis-LeMonda (Eds.) Child psychology (pp.116–139). New York: Psychology Press
  17. ^ a b Mueller & Sepulveda, V. & A. (2013). "Parental perception of a baby sign workshop on stress and parent- child interaction". Early Child Development and Care. 
  18. ^ Magnuson, Miriam (March 2000). "Infants with Congenital Deafness: On the Importance of Early Sign Language Acquisition". American Annals of the Deaf. 
  19. ^ Emmorey, Karen (2002). "Language, Cognition, and the Brain: Insights from Sign Language Research". Mahwah, NJ: Lawrence Erlbaum Associates. 
  20. ^ Youngwith, Janice (March 2011). "Baby Sign Language Opens Doors to Early Communication". The Daily Herald. 
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  22. ^ "Baby Signing". June 2011. 
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  24. ^ a b Bonvillian, John D.; Raymond J. Folven (1987). "The onsent of signing in young children". Paper Presented at the Fourth International Symposium on Sign Language Research, Lappeenranta, Finland. 
  25. ^ Capute, Arnold J.; Frederick B. Palmer; Bruce K. Shapiro; Renee C. Wachtel; Steven Schmidt; Alan Ross (1986). "Clinical Linguistics and Auditory Milestone Scale: Prediction of cognition in infancy". Developmental Medicine & Child Neurology 28: 762–71. doi:10.1111/j.1469-8749.1986.tb03930.x. 
  26. ^ Orlansky, Michael D.; John D. Bonvillian (1985). "Sign Language Acquisition: Language development in children of deaf parents and implications for other populations". Merrill-Palmer Quarterly 31: 127–43. 
  27. ^ Grabmeier, Jeff (25 January 1999). "Infants Use Sign Language to Communicate At Ohio State School". The Ohio State University. Archived from the original on 14 June 2010. Retrieved 10 January 2014. 
  28. ^ Volterra, V. Iverson, J.M. & Castrataro, M. (2006). The development of gesture in hearing and deaf children. In B. Schick et al. (Eds.) Sign language development. New York: Oxford University Press
  29. ^ Johnston, J., Durieux-Smith, A. & Bloom, K. (2005). Teaching gestural signs to infants to advance child development. First Language, 25, 235–251
  30. ^ a b Kirk, E. Howlett, N., Pine, K. J., & Fletcher, B. C. (2013). To sign or not to sign? The impact of encouraging infants to gesture on infant language and maternal mind-mindedness. Child Development, 84(2), 574-590. doi: 10.1111/j.1467-8624.2012.01874.x
  31. ^ a b Seal, B. C., & DePaolis, R. A. (2014). Manual activity and onset of first words in babies exposed and not exposed to baby signing. Sign Language Studies, 14(4), 444-465. doi:10.1353/sls.2014.0015
  32. ^ a b c d e Johnston, J., Durieux-Smith, A., & Bloom, K. (2005). Teaching gestural signs to infants to advance child development: A review of the evidence. First Language, 25(2), 235–251.
  33. ^ Pettito, Laura A. (1988). Frank S. Kessel, ed. "Language" in the pre-linguistic child. The development of language and language researchers. Hillsdale, NJ: Lawrence Erlbaum. pp. 187–221. 
  34. ^ Goldin-Meadow, Susan; Marolyn Morford (1985). "Gestures in early child language: Studies of deaf and hearing children". Merrill-Palmer Quarterly 31: 145–76. 
  35. ^ Meier, Richard P.; Elissa L. Newport (1990). "Out of the Hands of Babes: On a possible sign advantage in language acquisition". Language 66 (1): 1–23. doi:10.1353/lan.1990.0007. 
  36. ^
  37. ^ a b c Volterra, Virginia; Iverson, Jana M.; Castrataro, Marianna (2005). Brenda Schick, Marc Marschark, and Patricia Elizabeth Spencer, ed. Advances in the Sign Language Development of Deaf Children. Cary, NM, USA: Oxford University Press. pp. 46–70. 
  38. ^ Bonvillian, J. D., & Siedlecki, T. (2000). Young children’s acquisition of the formational aspects of American Sign Language: Parental report findings. Sign Language Studies, 1(1), 45-64. doi:10.1353/sls.2000.0002
  39. ^
  40. ^ Millennium Web Catalog. Retrieved on 5 January 2014.
  41. ^ Capirci, Montanari & Volterra 1998
  42. ^ Capirci, Iverson, Montanari, & Volterra 2002
  43. ^ [1] Archived 13 August 2009 at the Wayback Machine
  44. ^ Pizer, Walters, & Meier, G., K., & R. (2007). "Bringing up a baby with baby sign: Language ideologies and socialization in hearing families". Sign Language Studies. 
  45. ^ Nelson, White, Grewe, Lauri H, Karl R, Jennifer (2012). "Evidence for website claims about the benefits of teaching sign language to infants and toddlers with normal hearing.". Infant and Child Development. 
  46. ^ a b c Fitzpatrick, Thibert, Grandpierre, Johnston, Elizabeth M, Jonelle, Viviane, J Cyne (2014). "How handy are baby signs? A systematic review of the impact of gestural communication on typically developing, hearing infants under the age of 36 months". First Language. 

Further reading[edit]

External links[edit]