Language acquisition by deaf children

Language acquisition by deaf children parallels the development of any child acquiring spoken language as long as they are exposed to a fully accessible language from birth. Despite limited access to spoken language, communication and language exposure are fundamental to deaf infants' general cognitive development and their engagement with their surroundings. While a growing number of deaf children in the developed world receive hearing aids and/or cochlear implants to support spoken language acquisition, there are deaf communities around the world that use signed languages. Infants born to signing parents, or exposed immersively to fluent sign language models from a young age, generally acquire sign language natively.

Background

Human languages can be spoken or signed. Typically developing infants can easily acquire any language in their environment if it is accessible to them, regardless of whether the language uses the vocal mode (spoken language) or the gestural mode (signed language).

Deaf children who are exposed to an established sign language from birth learn that language in the same manner as any other hearing child acquiring a spoken language. Signed languages like ASL (American Sign Language) are, however, acquired by signers of varying age and are atypical from a language acquisition perspective. For example, only 5-10% of deaf children are born to deaf, signing parents in the United States. The remaining 90-95% of the signing community are deaf children born to hearing, non-signing parents/families who usually lack knowledge of signed languages and may discourage the use of a signed language in favor of spoken English.

These circumstances cause unique features of sign language acquisition not usually observed in spoken language acquisition. Due to the visual/manual modality, these differences can assist in distinguishing among universal aspects of language acquisition and aspects that may be affected by early language experience.

Acquisition of spoken language

Because 90-95% of deaf children are born to hearing parents, many deaf children are encouraged to acquire a spoken language. Deaf children acquiring spoken language use assistive technology such as hearing aids or cochlear implants, and work closely with speech language pathologists. Due to hearing loss, the spoken language acquisition process is delayed until such technologies and therapies are used. For children using hearing aids, spoken language outcomes in deaf children are correlated with the amount of residual hearing the child has. For children with cochlear implants, spoken language outcomes are correlated with or the amount of residual hearing the child had before implantation. Spoken language outcomes in deaf children with cochlear implants are highly variable.

For a detailed description of spoken language acquisition in hearing children see: Language acquisition.

For newborns, the earliest linguistic tasks are perceptual. Babies need to determine what basic linguistic elements are used in their native language to create words (their phonetic inventory). They also need to determine how to segment the continuous stream of language input into phrases, and eventually, words. From birth, they have an attraction to patterned linguistic input, which is evident whether the input is spoken or signed. They use their sensitive perceptual skills to acquire information about the structure of their native language, particularly prosodic and phonological features.

Cochlear implants

A cochlear implant is placed surgically inside the cochlea, which is the part of the inner ear that converts sound to neural signals. There is much debate regarding the linguistic conditions under which deaf children acquire spoken language via cochlear implantation. A singular, yet to be replicated, study concluded that long-term use of sign language impedes the development of spoken language and reading ability in deaf and hard of hearing children, and that using sign language is not at all advantageous, and can be detrimental to language development. However, studies have found that sign language exposure actually facilitates the development of spoken language of deaf children of deaf parents who had exposure to sign language from birth. These children outperformed their deaf peers who were born to hearing parents following cochlear implantation.

New parents with a deaf infant are faced with a range of options for how to interact with their newborn, and may try several methods, including different amounts of sign language, oral/auditory language training, and communicative codes invented to facilitate acquisition of spoken language. In addition, parents may decide to use cochlear implants or hearing aids with their infants. According to one US-based study from 2008, approximately 55% of eligible deaf infants received cochlear implants. A study in Switzerland found that 80% of deaf infants were given cochlear implants as of 2006 and the numbers have been steadily increasing. While cochlear implants provide auditory stimulation, not all children succeed at acquiring spoken language completely. Many children with implants often continue to struggle in a spoken-language-only environment, even when support is given. Children who received cochlear implants before twelve months old were significantly more likely to perform at age-level standards for spoken language than children who received implants later. However, there is research that shows that the information given to parents is often not correct or missing important information; this can lead them to make decisions that might not be the best for their child. Parents need time to make informed decisions. As most deaf children are born to hearing parents, they have to make decisions on topics they have never considered.

Research shows that deaf children who listen and speak to communicate, but do not use sign language, have better communication outcomes and social well-being than deaf children who use sign language. However, sign language is often only recommended as a last resort, with parents being told not to use sign language with their child. Though implants offer many benefits for children, including potential gains in hearing and academic achievement, they are unable to fix deafness. A child who is born deaf will always be deaf, and they will likely still face many challenges that a hearing child will not. There is also research that shows that early deprivation of language and sign language, before an implant is fitted can affect the ability to learn language. There is no definitive research that states whether implants or singing has the best outcomes. Ultimately the decision comes down to the parents to make the choices that are best for their child.

Acquisition of signed language

Children need language from birth. Deaf infants should have access to sign language from birth or as young as possible, with research showing that the critical period of language acquisition applies to sign language too. Sign languages are fully accessible to deaf children as they are visual, rather than aural, languages. Sign languages are natural languages with the same linguistic status as spoken languages. Like other languages, sign languages are much harder to learn when the child is past the critical age of development for language acquisition. Studies have found that children who learned sign language from birth understand much more than children who start learning sign language at an older age. Also, studies indicate that the younger a child is when learning sign language, the better their language outcomes are. There is a wide rage of ages at which deaf children exposed to a sign language and begin their acquisition process. Approximately 5% of deaf children acquire a sign language from birth from their deaf parents. Deaf children with hearing parents often have a delayed process of sign language acquisition, beginning at the time when the parents start learning a sign language or when the child attends a signing program.

Sign languages have natural prosodic patterns, and infants are sensitive to these prosodic boundaries even if they have no specific experience with sign languages. Six-month-old hearing infants with no sign experience also preferentially attend to sign language stimuli over complex gesture, indicating that they are perceiving sign language as meaningful linguistic input. Since infants attend to spoken and signed language in a similar manner, several researchers have concluded that much of language acquisition is universal, not tied to the modality of the language, and that sign languages are acquired and processed very similarly to spoken languages, given adequate exposure. These babies acquire sign language from birth and their language acquisition progresses through predictable developmental milestones. Babies acquiring a sign language produce manual babbling (akin to vocal babbling), produce their first sign, and produce their first two-word sentences on the same timeline as hearing children acquiring spoken language. At the same time, researchers point out that there are many unknowns in terms of how a visual language might be processed differently than a spoken language, particularly given the unusual path of language transmission for most deaf infants.

Because sign language is a visual language, eye gaze and eye contact are critical for language acquisition and communication. Studies of deaf parents who sign with their deaf children have shed light on paralinguistic features that are important for sign language acquisition. Deaf parents are adept at ensuring that the infant is visually engaged prior to signing, and use specific modifications to their signing, referred to as child-directed sign, to gain and maintain their children's attention. Just as in child-directed speech (CDS), child-directed signing is characterized by slower production, exaggerated prosody, and repetition. Due to the unique demands of a visual language, child-directed signing also includes tactile strategies and relocation of language into the child's line of vision. Another important feature of language acquisition that affects eye gaze is joint attention. In spoken languages, joint attention involves the caregiver speaking about the object that the child is looking at. Deaf signing parents capitalize on moments of joint attention to provide language input. Deaf signing children learn to adjust their eye gaze to look back and forth between the object and the caregiver’s signing.

Bilingual Language Acquisition

Some deaf children acquire both a sign language and a spoken language. This is called bimodal bilingual language acquisition. Bimodal bilingualism is common in hearing children of deaf adults (CODAs). One group of deaf children who experience bimodal bilingual language acquisition are deaf children with cochlear implants who have deaf parents. These children acquire sign language from birth and spoken language after implantation. Other deaf children who experience bimodal bilingual language acquisition are deaf children of hearing parents who have decided to pursue both spoken language and sign language. Some parents make the decision to pursue sign language while pursuing spoken language so as not to delay exposure to a fully accessible language, thereby starting the language acquisition process as early as possible. While some caution that sign language might interfere with spoken language, other research has shown that early sign language acquisition does not hinder and may in fact support spoken language acquisition.

Methods

For a review of educational methods including signing and spoken language approaches, see: Deaf education

Pedagogy

Language acquisition strategies for signing deaf children are different than those appropriate for hearing children, or for deaf children who successfully use hearing aids and/or cochlear implants. For parents with deaf children who do not use amplification (hearing aids or cochlear implants), joint attention (an important component to language development) can be problematic. Hearing children can watch their environment and listen to an adult comment on it. However, children who do not hear have to switch their visual attention back and forth between stimuli.

Strategies for nonverbal communication include using facial expressions and body language to show emotion and reinforce the child's attention to their caregiver. To attract and direct a deaf child's attention, caregivers can break his line of gaze using hand and body movements, touch, and pointing to allow language input. In order to make language salient, parents should use short, simple sentences so that the child's attention doesn’t have to be divided for too long. Finally, to reduce the need for divided attention, a caregiver can position themselves and objects within the child's visual field so that language and the object can be seen at the same time.

Speech and oral methods

For deaf children who: receive cochlear implants early in life, are born to parents who use spoken language in the home, and pursue spoken language proficiency, research demonstrates that L1 language and reading skills are consistently higher for those children who have not been exposed to a signed language as an L1 or L2, and have instead focused exclusively on listening and spoken language development. In fact, "Over 70% of children without sign language exposure achieved age-appropriate spoken language compared with only 39% of those exposed for 3 or more years." Children who focused primarily on spoken language also demonstrated greater social well-being when they did not use manual communication as a supplement.

For deaf children who are born to parents who use spoken language in the home, who receive cochlear implants early in life, and who pursue spoken language proficiency, research demonstrates that L1 language and reading skills are consistently higher for those children who have not been exposed to a signed language as an L1 or L2, and have instead focused exclusively on listening and spoken language development. In fact, "Over 70% of children without sign language exposure achieved age-appropriate spoken language compared with only 39% of those exposed for 3 or more years." Children who focused primarily on spoken language also demonstrated greater social well-being when they did not use manual communication as a supplement.

Signing and manual methods

Sign languages appear naturally among deaf groups even if no formal sign language has been taught. Natural sign languages are much like English and Spanish in that they are true languages, and children learn them in similar ways. They also follow the same social expectations of language systems. Some studies indicate that if a deaf child learns sign language, he or she will be less likely to learn spoken languages because they will lose motivation. However, Humphries insists that there is no evidence for this. One of Humphries arguments is that many hearing children learn multiple languages and do not lose the motivation to do so. Other studies have shown that sign language actually aids spoken language development. Understanding and using sign language provides the platform that is needed to develop other language skills. It can also provide the foundation for learning the meaning of written words. There are many different sign languages used around the world. Some of the main sign languages include American Sign Language, British Sign Language and French Sign Language.

American Sign Language (ASL)

ASL is mostly used in north America, though derivative forms are used in various places around the world including most of Canada. ASL is not simply a translation of English works, this is demonstrated by the fact that words that have dual meaning in English have different signs for each individual meaning in ASL.

British Sign Language (BSL)

BSL is mainly used in Great Britain, with derivatives being used in Australia and New Zealand. British sign language has its own syntax and grammar rules. It is different from spoken English though hearing people in America and the United Kingdom share a language, ASL and BSL are different meaning that deaf children in English speaking countries do not have a shared language.

French Sign Language (LSF)

LSF is used in France as well as many other countries in Europe. The influence of French sign language is apparent in other signed languages, including American sign language.

Manually coded English

Manually coded English is any one of a number of different representations of the English language that uses manual signs to encode English words visually. Although MCE uses signs, it is not a language like ASL; it is an encoding of English that uses hand gestures to make English visible in a visual mode. Most types of MCE use signs borrowed or adapted from American Sign Language, but use English sentence order and grammatical construction.

Numerous systems of manually encoded English have been proposed and used with greater or lesser success. Methods such as Signed English, Signing Exact English, Linguistics of Visual English, and others use signs borrowed from ASL along with various grammatical marker signs, to indicate whole words, or meaning-bearing morphemes like -ed or -ing.

Because MCE systems are encodings of English which follow English word order and sentence structure, it is possible to sign MCE and speak English at the same time. This is a technique that is used in order to teach deaf children the structure of the English language not only through the sound and lip-reading patterns of spoken English, but also through manual patterns of signed English. Because of the close connection between the two, it is easier for hearing people to learn MCE than ASL.

Cued speech

Cued speech is a hybrid, oral/manual system of communication used by some deaf or hard-of-hearing people. It is a technique that uses handshapes near the mouth ("cues") to represent phonemes that can be challenging for some deaf or hard-of-hearing people to distinguish from one another through speechreading ("lipreading") alone. It is designed to help receptive communicators to observe and fully understand the speaker.

Cued speech is not a signed language, and it does not have any signs in common with ASL. It is a kind of augmented speechreading, making speechreading much more accurate and accessible to deaf people. The handshapes by themselves have no meaning; they only have meaning as a cue in combination with a mouth shape, so that the mouth shape 'two lips together' plus one handshape might mean an 'M' sound, the same shape with a different cue might represent a 'B' sound, and with a third cue might represent a 'P' sound.

Some research shows a link between lack of phonological awareness and reading disorders, and indicate that teaching cued speech may be an aid to phonological awareness and literacy.

Fingerspelling

Another manual encoding system used by the deaf and which has been around for more than two centuries is fingerspelling. Fingerspelling is a system that encodes letters and not words or morphemes, so is not a manual encoding of English, but rather an encoding of the alphabet. As such, it is a method of spelling out words one letter at a time using 26 different handshapes. In the United States and many other countries, the letters are indicated on one hand and go back to the deaf school of the Abbe de l'Epee in Paris. Since fingerspelling is connected to the alphabet and not to entire words, it can be used to spell out words in any language that uses the same alphabet. It is not tied to any one language in particular, and to that extent, it is analogous to other letter-encodings, such as Morse code, or semaphore. The Rochester Method relies heavily on fingerspelling, but it is slow and has mostly fallen out of favor.

Hybrid methods

Hybrid methods use a mixture of aural/oral methods as well as some visible indicators such as hand shapes in order to communicate in the standard spoken language by making parts of it visible to those with hearing loss.

One example of this is sign supported English (SSE) which is used in the United Kingdom. It is a type of sign language that is used mainly with children who are hard of hearing in schools. It is used alongside English and the signs are used in the same order as spoken English.

Another hybrid method is called Total Communication. This method of communication allows and encourages the user to use all methods of communication. These can include spoken language, signed language and lip reading. Like sign-supported English, signs are used in spoken English order. The use of hearing aids or implants is highly recommended for this form of communication. It is only recently that ASL has been an accepted form of communication to be used in the total communication method.

Reading

According to Goldin-Meadow, reading requires two essential abilities: familiarity with a language and understanding the mapping between that language and the written word. However, reading is possible if deaf children learn ASL. Once they have acquired ASL, deaf children learn how to map between sign language and print so that they can learn English. Several techniques are used to help bridge the gap between ASL and spoken language or the "translation process" such as sandwiching and chaining.

Sandwiching consists of alternating between saying the word and signing it. Chaining consists of finger spelling a word, pointing to the spoken language version of the word and using pictorial support. Although chaining is not widely used, it creates an understanding between the visual spelling of a word and the sign language spelling of the word. This helps the child become bilingual in both ASL and spoken language.

The deaf child's social context is crucial for nurturing his or her capacity to read. Research shows that deaf children born to deaf parents are usually better readers than deaf children born to hearing parents. This is because deaf parents provide a strong social and emotional network and may immediately have access to the necessary resources for their child. Deaf parents already anticipate the needs of their child, having been through the same experience, as opposed to a hearing parent.

Ethics and language acquisition

Cochlear implants have been the subject of a heated debate between those who believe deaf children should receive the implants and those who do not. Certain deaf activists believe this is an important ethical problem, claiming that sign language is their first or native language, just as any other spoken language is for a hearing person. They do not see deafness as a deficiency in any way, but rather a normal human trait amongst a variety of different ones. One issue on the ethical perspective of implantation is the possible side effects that may present after surgery. However, complications from cochlear implant surgery are rare, with some centers showing less than a three percent failure rate.

Relationship between language acquisition and other domains of development

Cognitive development

Early exposure and access to language facilitates healthy language acquisition, regardless of whether or not that language is native or non-native. in turn, strong language skills support the development of the child's cognitive skills, including executive functioning. Studies have shown that executive functioning skills are extremely important, as these are the skills that guide learning and behavior . Executive functioning skills are responsible for self-regulation, inhibition, emotional control, working memory, and planning and organization, which contribute to overall social, emotional and academic development for children. Early access to a language, whether signed or spoken, from birth supports the development of these cognitive skills and abilities in deaf and hard of hearing children, and supports their development in this area.

However, late exposure to language and delayed language acquisition can inhibit or significantly delay the cognitive development of deaf and hard of hearing children, and impact these skills. Late exposure to language can be defined as language deprivation (see Language deprivation in deaf and hard of hearing children). This experience is the result of a lack of exposure to natural human language, whether that be spoken or signed language, during the critical language period. According to World Health Organization, approximately 90% of deaf children are born to hearing parents; hearing parents that more often than not, and through no fault of their own, are not prepared to provide an accessible language to their children, therefore, some degree of language deprivation occurs in these children. Language Deprivation has been found to impair deaf children’s cognitive development, specifically their executive functioning skills and working memory skills, causing deficits in critical executive functioning skills and overall cognitive development. It is not deafness that causes these deficits, but delayed language acquisition that influences the cognitive development and abilities of deaf people.

Social-emotional development

Having an acquired language means an individual has had full access to at least one spoken or signed language.Typically, if a person has had this full access to language and has been able to acquire it, the foundation for their social emotional development is present Being able to communicate is critical for those still developing their social skills. There is also evidence to suggest that language acquisition can play a critical role in developing Theory of Mind. For children who have not had this access or have not yet fully acquired a language, social development can be stunted or hindered, which in turn can affect one’s emotional development as well.

The lack of socialization can significantly impact a child’s emotional well-being. A child’s first experience with social communication typically begins at home, but deaf and hard of hearing children in particular who are born to hearing parents tend to struggle with this interaction, due to the fact that they are a “minority in their own family". Parents who have a deaf child typically do not know a signed language, the logistical problem becomes how to give that child exposure to language that the child can access. Without a method of communication between the child and parents, facilitating their child’s social skill development at home is more difficult.  By the time these children enter school, they can be behind in this area of development. All of this can lead to struggles with age appropriate emotional development. It will be hard on a child who was not given a language early in life to try and express their emotions appropriately. The problem is not caused by deafness, it is caused by lack of communication that occurs when there is a lack of language access from birth. There is evidence to suggest that language acquisition is a predictor of how a child’s ability to develop theory of mind . Theory of mind can be an indicator of social and cognitive development. Without language acquisition, deaf children can become behind in theory of mind and the skills that coincide, which can lead to further social and emotional delays.

Academic development

Second language acquisition is also highly affected by early language exposure. More exposure in an accessible language leads to better performance in the second language upon entering school. Providing deaf and hard of hearing children with the most fluent language exposure possible from the earliest age possible promotes both first and second language acquisition. This means giving students the opportunity to develop language at home and in social environments early on supports the child's language acquisition in American Sign Language as well as printed English. There is extensive research regarding the correlation between proficiency in ASL and proficiency in English literacy skills. Deaf students who use ASL as their primary language tend to have higher English reading and writing scores when they also have a higher proficiency in ASL. There is also research to support that the development of a second language also improves proficiency in the student's first language

According to Hrastinski & Wilbur (2016), American Sign Language proficiency is the single most contributing factor to the academic achievement of Deaf students who attend schools that teach with American Sign Language, particularly in the areas of reading literacy and math. Deaf and hard of hearing children who have higher levels of American Sign Language proficiency and those who have higher proficiency in a second language (e.g., English) are those who were exposed to American Sign Language during the critical period of language.

See also

• Bilingual education
• American Sign Language
• Classifiers in American Sign Language
• Language acquisition
• Deaf Education
• Language deprivation in deaf and hard of hearing children
• Bimodal bilingualism
• Pointing

Further reading

• Meier, R. (1991). Language Acquisition by Deaf Children. American Scientist (Vol. 79, pp. 60–70). Sigma Xi, The Scientific Research Society.
• Pinker, S.; Jackendoff, R. (2005). "The faculty of language: what's special about it?". Cognition. 95 (2): 201–236. CiteSeerX 10.1.1.494.2923. doi:10.1016/j.cognition.2004.08.004. PMID 15694646.
• Paul, P. (2009). Language and Deafness. 4th Edition. Sudbury: Jones & Bartlett Learning.
• Mohay, H., Milton L., Hindmarsh, G. & Ganley K. (1998). Deaf Mothers as Communication Models for Hearing Families with Deaf Children. In Weisel, A. (Ed.), Issues Unresolved: New Perspectives on Language and Deaf Education (pp. 76–87). Washington: Gallaudet University Press.
• Bowe, F (1998). "Language Development in Deaf Children". Journal of Deaf Studies and Deaf Education. 3 (1): 73–77. doi:10.1093/oxfordjournals.deafed.a014342.
• Scott, S & Simms, L. (2012). Everything You Always Wanted to Know About ASL/English Bimodal Bilingual Education [Handout].
• Goldin-Meadow, S.; Mayberry, R. (2001). "How Do Profoundly Deaf Children Learn to Read?". Learning Diabilities Research & Practice. 16 (4): 222–229. doi:10.1111/0938-8982.00022.
• Meadow, K (2005). "Early Manual Communication in Relation to the Deaf Child's Intellectual, Social, and Communicative Functioning". Journal of Deaf Studies and Deaf Education. 10 (4): 321–329. doi:10.1093/deafed/eni035. PMID 16000694.
• Svirsky, M.; et al. (2000). "Language Development in Profoundly Deaf Children With Cochlear Implants". Psychological Science. 11 (2): 153–158. doi:10.1111/1467-9280.00231. PMC 3429133. PMID 11273423.
• Goldin-Meadow, S. et al. (1984). Gestural Communication in Deaf Children: The Effects and Noneffects of Parental Input on Early Language Development. Monographs of the Society for Research in Child Development (Vol. 49, pp. 1–151). Wiley.
• Examining Chomsky's Inborn Universal Grammar Theory. (n.d.). In Boundless. Retrieved November 11, 2013.
• Cochlear Implants - Benefits and Risks of Cochlear Implants. (September 8, 2010). In U.S. Food and Drug Administration. Retrieved November 11, 2013.
• American Sign Language. (June 2011). In National Institute on Deafness and Other Communication Disorders (NIDCD). Retrieved November 11, 2013.
• Humphries, T.; et al. (2012). "Language acquisition for deaf children: Reducing the harms of zero tolerance to the use of alternative approaches". Harm Reduction Journal. 9: 16. doi:10.1186/1477-7517-9-16. PMC 3384464. PMID 22472091.{{cite journal}}: CS1 maint: unflagged free DOI (link)
• Courtin, C (2000). "The Impact of Sign Language on the Cognitive Development of Deaf Children: The Case of Theories of Mind". Journal of Deaf Studies and Deaf Education. 5 (3): 266–276. doi:10.1093/deafed/5.3.266. PMID 15454505.