Parallel Language Development in Deaf and Hearing Children
Parallel Language Development in Deaf and Hearing Children Parallel Language Development in Deaf and Hearing Children Much of the past research on language development has focused on auditory language learned by hearing children. Recently, researchers such as Jamieson (1995) and Masataka (1992) have begun to study whether language acquisition proceeds in the same manner for deaf children as for hearing children. Results from studies of hearing children learning different languages have shown that the first stage in the acquisition of language is babbling, which usually appears between 7 and 10 months (Lane, Hoffmeister, & Bahan, 1996). Next, between the ages of 12 and 18 months, children make one-word utterances, and by 22 months, most children are at the two-word utterance stage. Children begin to modify words and learn rules for sentence construction by 36 months (Lame at al., 1996). Parents play an important role in the language development of their children. One unique manner in which parents, and many other adults, talk to children is called "motherese." Motherese is characterized by short sentences, changes in voice fluctuation, slow tempo, and repetition of words. The properties of motherese are thought to enhance early language acquisition by eliciting the infant's attention and demonstrating important aspects of the language (Masataka, 1992). Also, the richness of the language environment the child is exposed to, usually measured by the frequency and type of word the child hears, is positively correlated with the development of language (Levine, 1981). Children also take active control of language learning. Through babbling, by which an infant repeats consonant and vowel combinations, the child gains experience in language. Once the child reaches the level of speaking word sequences in the native language, ha or she begins to acquire grammatical rules for sentences (Bark, 1997). Although children in this stage frequently make grammatical mistakes, these mistakes are evidence that children are learning and thinking about grammatical rules (Croweon, 1994). private speech, or speech that is spoken aloud but not meant for the benefit of others, is another milestone in the language development of children. Private speech is a factor in cognitive development that helps link thought and language (Jamieson, 1995). Language Development in Deaf Children So far, language acquisition has only been discussed in terms of children who learn language by hearing those around them speak. However, there is a substantial subset of children who cannot do this because they are deaf. Most of the research in the past dealing with language development has focused on hearing children, and many of the ideas which coma from that research have had an auditory basis. Recently, researchers have begun studying deaf children to sea if their processes of acquiring language are similar to those of hearing children. Researchers have studied whether parents of deaf infants use a type of motherese in their communications with their infants and whether the signed language environment has an effect on the language development of children (Masataka, 1992; Spencer, 1993). Also, other researchers have focused on whether babbling occurs in deaf children and whether deaf children use a form of private speech (Petitto & Marentetta, 1991; Cook & Harrison, 1995). In addition, some research has looked at the errors deaf children make in learning sign language and has compared them to errors made by hearing children learning spoken language (Crowson, 1994). Motherese. One experiment to determine whether deaf mothers use a form of manual motherese
to communicate with their deaf babies was performed by Masataka (1992). Eight deaf mothers whose first learned language was Japanese Sign Language were each observed interacting with her firstborn deaf infant and also with an adult deaf friend who also signed in Japanese Sign Language. These interactions ware videotaped and the signs were transcribed by two independent observers who recorded the duration of signs, the levels of exaggeration of the signs, and the number of repeated signs Masataka found that the mothers repeated significantly more signs when communicating with their infants than when communicating with their adult friends. Also, the ...
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to communicate with their deaf babies was performed by Masataka (1992). Eight deaf mothers whose first learned language was Japanese Sign Language were each observed interacting with her firstborn deaf infant and also with an adult deaf friend who also signed in Japanese Sign Language. These interactions ware videotaped and the signs were transcribed by two independent observers who recorded the duration of signs, the levels of exaggeration of the signs, and the number of repeated signs Masataka found that the mothers repeated significantly more signs when communicating with their infants than when communicating with their adult friends. Also, the duration of the individual signs directed toward the infants was longer than signs directed toward the adults. Finally, the mean scores for the maximum and average values of the angles for each sign were significantly larger when the signs were aimed at the infant. These results led Masataka (1992) to conclude that deaf mothers do use a manual form of motherese when communicating with their deaf infants. As in spoken motherese, there was more repetition of symbols, a slower rate of delivery, and exaggerated presentation. Masataka suggested that manual motherese elicits stronger responses from infants and helps them to better acquire sign language. Sign Language Development and Hearing Parents. Hearing parents can also benefit their deaf children by using sign language as a form of communication. Spencer (1993) observed the play between seven mothers and their deaf. infants. The families were all participants in various intervention programs that were designed to help deaf children acquire language. A trained professional spent three to five hours per week in the home teaching parents sign language and providing other services for the parents and infant. Researchers observed the mother and child playing together and recorded the language productions of the infants and the mothers. The mothers also took part in three structured interviews. Spencer reported that mothers who signed often when their infants were 12 months old continued to sign, often more frequently, when their infants were 18 months old. The sign production of infants at 18 months was positively correlated with the number and variety of signs that mothers produced six months earlier. She also found that some of the infants were capable of expressive language during the same time frame as their hearing counterparts, even though the number of signs produced by the deaf infants' mothers did not reach the number of words spoken by mothers of hearing children. Spencer (1993) concluded from these results that infants' acquisition of sign language was related to the quantity of signs the mother had used. In general, an environment rich in signing, even non-fluent signing, helped the infants acquire language in a tine frame equal to that of hearing children. "Sign Babbling" and Private Speech. Deaf and hearing children also exhibit similarities in the early stages of language acquisition. Petitto and Harentette (1991) gathered experimental and naturalistic data from two deaf infants of deaf parents and three hearing infants of hearing parents. The deaf infants ware in the process of acquiring American Sign Language (ASL) as their first language, and the hearing infants ware not exposed to sign language. All infants' manual activities were recorded and examined for evidence of sign babbling. Petitto and Marentette found that although deaf and hearing infants displayed equal numbers of gestures, deaf infants produced more sign babbling than did hearing infants. The deaf infants engaged in manual babbling by 10 months of age (the youngest age tested), the same tine frame in which their hearing counterparts developed vocal babbling. Furthermore, stages of sign babbling paralleled stages of vocal babbling, and, as in vocal babbling, frequently used phonetic units in sign babbling were involved in the most frequent first babbling units of deaf infants. Because of these parallels between manual babbling in deaf infants and vocal babbling in hearing infants, Petitto and Marentette (1991) concluded that language acquisition was universal and not reliant on the development of the vocal tract. Instead, they argued, because babbling occurred at approximately the same time in hearing and deaf infants, language acquisition was based on a timetable of brain maturation. This brain language capacity was able to process different types of signals, both manual and vocal, resulting in similarities in language development between deaf and hearing infants. Another similarity between language development of deaf and hearing children is the occurrence of private signing in deaf children. Private signing has the same characteristics and serves the same function as private speech does for hearing children (Cook & Harrison, 1995). Private speech is uttered aloud, but is not produced for the benefit of communicating with others. In the Cook and Harrison study, teachers filled out one survey for the most literacy-developed and the least literacy-developed preschool students and gave the parents of these selected students surveys to complete. The surveys included a section on private signing that was answered only by teachers and parents of students who used sign language. Cook and Harrison found that a high percentage of both the most advanced and least advanced students used private sign in the classroom and at home, although the advanced students showed a greater incidence in some learning Situations. Deaf children signed to themselves when they read privately as well as when they played with toys and acted out stories. Also, private sign was used to express emotions and for self-regulation. Hearing children use private speech for all these activities. In another study, Jamieson (1995) examined the use of private speech between two groups of deaf children. One group consisted of three deaf children with hearing mothers, and one consisted of three deaf children with deaf mothers. All mother-child dyads that included hearing mothers came from homes where English was the primary language, while all dyads that included deaf mothers used ASL as the primary language in the home. Jamieson presented each child with a task that was originally beyond his or her ability level. The mother was asked to teach the child how to complete the task, and then the child performed the task alone. Jamieson observed that children of deaf mothers used private speech in a signed form. Deaf children of hearing mothers also used private speech, but at only 20 percent of the frequency of those with deaf mothers. Jamiesom (1995) also concluded that children of deaf mothers use S more mature form of private sign. Her study showed that their signs were more task oriented and were used to guide and monitor their performance. In addition to the greatly reduced frequency of private sign among deaf children of hearing mothers, one-third of these signs were not task related, involving instead word play and repetition. Jamieson attributed this discrepancy between groups to differences in language exposure. Unlike children of hearing mothers, those with deaf mothers had been exposed to ASL from birth. Therefore, their signed language environment was richer and more conducive to development. A shared language between parent and child seems to facilitate the development and use of private sign. Types of Errors. Another important aspect in the development of language is the type of errors children make when acquiring language. Crowson (1994) studied videotapes of six deaf children from hearing families to determine what types of errors they made in signing. Errors were divided into four categories. phonological, morphological (errors and omissions), overgeneralizations, and other types of errors. Crowson found that phonological errors were the most common, with handshape, movement, and orientation being the most common. Although morphological errors and overgeneralizations were also made, most of the children had not yet reached the level of signing where those errors would have occurred. Crowson (1994) concluded that errors made by deaf children were parallel to errors made by hearing children at similar stages of language acquisition. The phonological errors in signing matched pronunciation errors made by hearing children. Handshape, movement, and orientation errors consisted of units from the sign language that the children were learning. Crowson also concluded that the overgeneralizations and morphological omissions matched semantic overgeneralization and morphological errors made by hearing children. Thus, it can be concluded that deaf children tend to acquire language in approximately the same manner as hearing children. Just as parents of hearing children help their children develop language by using motherease and by providing a rich language environment, parents of deaf children help their children in the same manner (Bark, 1997) Deaf parents tend to use a manual form of motherease (Masataka, 1992) and parents who show a higher frequency of signing produce deaf children with better signing skills (Spencer, 1993). Deaf children exhibit sign babbling at the same time periods and with the same uses as bearing babies (Petitto & Harentette, 1991). In addition, deaf children use a form of private speech, termed private sign, that is similar to private speech in hearing children (Cook & Harrison, 1995; Jamieson, 1995). Differences between Deaf and Hearing Children Despite the parallels of language development between deaf and hearing children, there are also important differences. Deaf children as a whole have been shown to develop language skills at a slower rate than hearing children (Meadow, 1980). Within the deaf-children group, there is a large difference between language acquisition of deaf children with deaf parents and that of deaf children of hearing parents. Deaf children of deaf parents are more similar to hearing children of hearing parents because the parents and child share a common form of language (Lane at al., 1996). Deaf children of hearing parents, on the other hand, have a more difficult time learning language because they typically will not develop the same natural language as their parents. Thus, there is little or no parent-child linguistic communication (Lane at al., 1998). These differences become more apparent when children reach school age. Deaf children of deaf mothers have higher reading and writing scores than their counterparts with hearing mothers (Meadow, 1980). Although most deaf children score in the normal range on IQ tests, they perform below their potential in school. These children, most of whom have hearing parents, have not reached the level of language comprehension and usage that allows them to function well in academic settings (Meadow, 1980). Language also affects social and behavioral aspects of deaf children. Deaf children of hearing parents have less exposure to language, delaying language development. This limits their social interaction. They also have more behavioral problems than deaf children of deaf parents (Meadow, 1980). Levine (1981) suggests that the shared language experienced by deaf children of deaf parents fosters better communication skills, producing fewer interpersonal difficulties. Deaf children of deaf parents are rated as more mature by their teachers than deaf children of hearing parents (Meadow, 1980). One other difference between language acquisition of deaf and hearing children relates to individual differences. Probably due to the language environment that the child is raised in, there are greater individual differences in language development of deaf children. It is vitally important that deaf children be exposed to some type of manual communication. Deaf children need to be able to understand what is going on around them and to communicate their needs and feelings to others. Studies have shown that learning sign language does not inhibit learning oral language (Meadow, 1980), 50 parents should give their deaf children every opportunity to learn sign language. Also, to foster parent-child communication, parents should themselves learn sign language. Every child should be able to communicate with his or her own family. Future Research Future research into language development in deaf children should focus on obtaining larger sample sizes. Nearly all the studies reported in this paper used small sample sizes (usually six or seven children) . Since only 1 in 1000 children under the age of three is deaf, the sample population is reduced to begin with (Schein, 1989). Small sample sizes reduce generalizability and lead to questions about the general applicability of the results. Studies like that of Cook and Harrison (1995) that have examined private sign and like that of Petitto and Marentette (1991) that have examined sign babbling have valid designs that could be replicated and extended by using larger numbers of participants. Research into language development in deaf children has barely begun. It was not long ago that sign language was not considered to be a "natural language." Hockett (1960) suggested that one linguistic universal, that is, one characteristic of all natural languages of the world, was use of sound and voice for communication. Recent research, pointing out the similarities between language development of deaf and hearing children, has clearly identified sign language as parallel to spoken language. However, much yet remains to be discovered about the characteristics of sign language development. References Bark, L. F. (1997). Child development (4th ad.). Needham Heights, MA: Allyn and Bacon. Cook, J. H., & Harrison, M. (1995). Private sign & literacy development in preschoolers with hearing loss. Sion Language Studies, 88, 201-226. Crowson, K. (1994). Errors made by deaf children acquiring sign language. Early Child Development and Care, 99, 63-78 Hockett, C. F. (1960). The origin of speech. Scientific American, 203, 89-96. Jamieson, J. R. (1995). Visible thought: Deaf children's use of signed & spoken private speech. Sign Language Studies, 86, 63-80. Lane, H., Hoffmeister, R., & Bahan, B. (1996). A journey into the deaf-world. San Diego: Dawn Sign Press. Levine, B. S. (1981). The ecology of early deafness: Guides to fashioning environments and psychological assessment. New York: Columbia University Press. Masataka, N. (1992). Motherese in a signed language. Infant Behavior and Development, 15, 453-460. Meadow, K. P. (1980). Deafness and child development. Los Angeles: University of California Press. Petitto, L. A., & Marentette, P. F. (1991). Babbling in the manual mode: Evidence for the Ontogeny of language. Science, 251, 1493-1496. Schein, J. D. (1989). At home among strangers. Washington, DC: Gallaudet University Press. Spencer, P. E. (1993). The expressive communication of hearing mothers and deaf infants. American Annals of the Deaf, 138, 275-283.
