Maternal speech to children with Down Syndrome: an update.
Recent research on maternal speech to children with Down Syndrome (DS) generally corroborates studies conducted in the 1970s and 1980s. Specifically, the characteristics of language used by parents when speaking to children with mental retardation closely matches the characteristics of language addressed to typical children with the same language age. The question remains, however, why the language of children with DS develops more slowly and sometimes never reaches adult levels. This question is examined in reference to nativistic and learning theory frameworks. Keywords: language development, Down Syndrome, child-addressed speech, maternal speech, language environment, nativism, learning theory.
Early Studies of Child-Addressed Speech
Early studies of child-addressed speech examined the nature of maternal language input to typically developing (TD) language-normal children (Broen, 1972; Snow, 1972). Additionally, researchers analysed the verbal relationships between cognitively-normal adults and institutionalized adults with mental retardation (MR) (Siegel, 1963a,b,c, 1967; Siegel & Harkins, 1963; Spradlin & Rosenberg, 1964). In combination, these studies led researchers to question whether the language input to children with MR could be considered appropriate for their level of language development.
Buium, Rynders, and Turnure (1974) assessed this question by comparing mother-child verbal interactions in a sample of TD children versus children with DS matched to the TD children for chronological age (CA=2 years). Data were collected in the laboratory while individual child-parent dyads engaged in collaborative play and in an instructional task. Results included statistically significant differences between the two samples of mothers regarding numerous aspects of the speech addressed to the children, and all differences suggested that the language addressed to TD children was more sophisticated than the language addressed to children with DS. The mothers of children with DS were observed to direct higher proportions of imperatives to their children than did the mothers of TD children.
Buium et al. interpreted these results as demonstrating that the linguistic environment of languagelearning children with DS is different from that of TD children and therefore worthy of careful consideration in any attempt to understand the language delays of the former. Buium et al.'s interpretation was supported by independent research (e.g., Kogan, Wimberger, & Bobbitt, 1969; Marshall, Hegrenes, & Goldstein, 1973) showing that mothers of DS children are more directive and less likely to invite their child to take the lead in dyadic interaction than are the mothers of the CA-matched TD children. There was a shared belief in the specialized literature of the early- and mid-seventies that the differences in the language environment of TD children and children with MR had a negative influence on the language development of children with MR (e.g., Seitz, 1975; Mahoney, 1975; Mahoney & Seely, 1976; Mitchell, 1976; Levi & Zollinger, 1981). Such a belief was sometimes echoed without nuance as, for example, in Dolley (1974) who characterized adult and maternal speech to children with MR with respect to the restricted linguistic codes defined in Bernstein's early work on lower-social classes (Bernstein, 1961, 1964).
The observation that mothers of children with MR tend to be more directive than mothers of CAmatched TD children (particularly in teaching situations) may not at all be due to a teaching style that is specific to mothers of children with MR. Instead, Rondal (1978a) argued that it may reflect the perceived necessity of these mothers to participate more actively in prompting the learning of their children with developmental delays.
A major methodological problem in the early studies relates to the strategy of matching control group children by chronological age (CA). As demonstrated in the studies of the '70s and '80s, parental speech to language-learning TD children is closely related to the levels of language comprehension and production of the children (cf. Rondal, 1985, for a full analysis). Therefore it may be not so much the CAs of the children with MR that matter in the regulation of the verbal interactions between parents and children but rather the linguistic levels of the children. This point was demonstrated in several studies that appeared in the late '70s (Rondal, 1976, 1978a; Gutmann & Rondal, 1979; Buckhalt, Rutherford, & Goldberg, 1978; Cunningham, Reuler, Blackwell, & Deck, 1981; Petersen & Sherrod, 1982; Maurer & Sherrod, 1987; Mahoney, 1988). In fact, when children with MR are matched with TD for level of language development, maternal language input does not differ substantially across groups.
Rondal (1976, 1978a) analyzed 20 measures of maternal speech output, including numerical, lexical, semantic-structural, semantic-pragmatic, and language-teaching aspects. Included in the latter category were proportions of verbal approval and disapproval of children's utterances, utterances produced to catch the attention of the child, self-repetitions, frontal auxiliaries, expansions of children's utterances, explicit corrections of children's utterances, and repetitions of the child's utterances. The study covered the interval of development from 3 to 12 years-CA in the DS children. In contrast to the absence of differences in maternal speech to TD children vs. children with DS at corresponding MLUs (mean length of utterances levels), numerous significant differences were recorded in maternal speech depending on the language levels of the children. This confirmed that expressive language level is a far more powerful factor influencing maternal speech than whether the children are TD or have MR.
In a rare study that included both fathers and mothers of DS children, Maurer and Sherrod (1987) observed no marked differences in the verbal behaviors of the fathers of DS children vs. fathers of developmentally matched TD children. These findings replicated the basic similarity between mothers' and fathers' speech found in parental speech to TD children (Golinkoff & Ames, 1979; Rondal, 1980; Bredart-Compernol, Rondal, & Peree, 1981).
To the best of our knowledge, the role of language comprehension by children with MR has not been studied systematically to assess its potentially (co-)determining regulatory role regarding maternal speech. Some correlational data gathered with TD children (Cross, 1977, 1980; Furrow, Nelson, & Benedict, 1979) suggest that even if the child's productive level largely contributes to fixing the average formal complexity of parental speech, his or her receptive ability determines the maximal complexity of the latter at any time. This hypothesis is all the more likely to be correct given that the child's verbal comprehension is directly related to the efficiency of parental instructions. This pragmatic motivation is obviously central in dealing with children's behaviors, particularly in the case of the younger ones.
More Recent Contributions
Perhaps not surprisingly (given that the basic problems could be considered as largely solved in the earlier studies), fewer works have been published in more recent years on mothers' speech to languagelearning children with MR. A bibliographic search in the world databases PsycINFO and ERIC, in the first part of 2006, yielded only three independent sources over the last twenty years. We briefly review these contributions in what follows. With one exception, they are in agreement with the preceding stance.
Hooshyar (1987a; also 1986; 1987b) collected data on language patterns in the interactions of mother-child dyads involving 20 TD children and 20 children with DS. The children in each group were matched for MLU, and their ages ranged from 38 to 107 months. Interactions were videotaped for 20 minutes during free play and mealtime. The utterances of the partners were coded according to seven categories: query, declarative, imperative, performative, feedback, imitation, and self-repetition. The children were divided into two groups: those with a lower MLU [below 1.75; following Brown's (1973) criteria] and those with a higher MLU (beyond 1.75). Data from the mothers were analysed according to a four-way coding scheme: (1) utterances not influenced by the child's condition (TD vs. DS); (2) utterances influenced only by the child's MLU; (3) utterances influenced by the child's condition; and (4) utterances influenced by both condition and MLU. Results confirmed the child's linguistic ability as the primary determinant of maternal speech. Mothers' speech directed to children with DS and to MLUmatched TD children were not significantly different. In both conditions, overall more queries and a larger total number of utterances were directed to children with lower MLU, whereas imitation strategy was employed more with children who had a higher MLU.
Harris (1995) explored five aspects of maternal style: joint attention, topic control, responsiveness, object reference, and directives. Her sample included mother-child dyads involving 28 children with DS and 17 TD children. All children were at the holophrastic stage of language development at the beginning of the study. Their language was assessed at the time of recruitment and thirteen months later with the Reynell Developmental Scales. Both groups of mothers used similar strategies for labelling objects, responding to the children's vocalizations, and for directives. The mothers of children with DS did not appear to be more directive than the mothers of the TD children. The former mothers spent more time in joint attention and devoted more time to toys than the latter. This may have to do with a greater immaturity among children with DS than among TD children even when matched on early language level. For children in both groups, maternal language inside joint attention was positively associated with language gains whereas maternal language outside of joint attention was negatively associated with language gains. TD children appeared more sensitive to maternal language in the sense that they made more progress on related aspects of their language than did the children with DS during the interval of time covered by the study.
Cardoso-Martins and Mervis (1985; also Martins, 1985) examined the linguistic environment of five prelinguistic children with DS (CAs: 21 to 37 months) matched for level of development, CA, and MA, respectively, to three groups of TD children (in the MA-matched group, TD children had MAs between 13 and 18 months). Mothers and children participated in a 45-minute free-play session at home using a chosen set of toys. The language of the mothers of children with DS differed from that of the mothers of each group of TD children. Mothers of the children with DS used more imperatives and fewer nominal deictics (e.g., This is a ball) and nouns vs. pronouns. Cardoso-Martins and Mervis (1985) claim that mothers of children with DS contribute to the delayed lexical development of their offspring by failing to provide them with a sufficient amount of referent-label pairings. As noted by Rosenberg and Abbeduto (1993), Cardoso-Martins and Mervis' (1985) implication is unwarranted. They have not established a causal relation between maternal labelling behaviors and children's vocabulary development.
In later works, Mervis and Bertrand (1994, 1995) showed that besides MA (Barrett & Diniz, 1989; Rondal, 1985, 2002) particular cognitive strategies (e.g., mutual exclusivity, entire object reference, novel name--nameless category principles) play an important role in receptive lexical development, favoring a first identification of the target referents and their pairing with conventional labels. Once children with DS have begun to use at least some of these strategies, like younger TD children do, they acquire vocabulary items more rapidly. The observation that mothers of prelinguistic infants with DS use fewer nominal deictics and nouns (the two measures being correlated) than mothers of TD prelinguistic infants, even if valid (given that it has not been replicated in other studies) does not demonstrate that maternal speech to prelinguistic infants with DS is detrimental to lexical development.
There has been, to our knowledge, only one other study conducted on mother-child verbal-vocal interactions at the prelinguistic stage. Specifically, Jones (1977) studied the communicative patterns of dyads involving prelinguistic TD children and children with DS for a period of 3 months. She found that the infants with DS were less involved in child-dependent interactions (i.e., interactions in which the mothers followed the child's initiative). In contrast, DS infants were more involved in mother-directed interactions. It is likely that being maturationally delayed, prelinguistic infants with DS (a kind of CA-matching, in fact, even if it may appear to be a match on "linguistic level") are not comparable to TD infants at the very start of lexical development (as in Cardoso-Martins & Mervis' study). It may be all the more difficult for mothers of DS infants at this stage given the often described greater passivity of their offspring to assess developmental level with any degree of precision. Lastly, one will recall for the sake of the present argument, that it is only when the TD child starts his/her "genuine" linguistic development, that is with the first conventional words, that parental adaptations reach maximal sensitivity regarding the children's language level (i.e., the time at which maternal MLUs are lowest in average values) (cf. Rondal, 1985).
Leaving aside the inconclusive indication of Cardoso-Martins and Mervis (1985), it seems that the conclusions reached in the earlier studies on maternal language to language-learning DS children are supported by the more recent studies. The linguistic environment supplied by the mothers of children with DS appears indeed to supply the sort of Vygotskyan zone of proximal development that may be considered essential for first language acquisition.
The basic soundness, formally and functionally, of maternal language to language-learning children with DS does not imply that nothing could be done to further adapt this input in order to favor a more rapid language acquisition in these children. Ways to render the input to children with MR more salient regarding particular aspects that the child happens to be dealing with in her/his development at given moments can be implemented. Demonstrating this point is the clinical research published by Cheseldine and McConkey (1979). These researchers succeeded in favoring a more rapid passing than usually observed from the one-word stage of expression to a level including a high frequency of two-word utterances, in children with moderate MR (including children with DS), by having the parents markedly reducing the length and complexity of their speech to their children during experimental sessions conducted at home.
Although it is not by far an easy task to monitor parental input (if only a few hours a week), parents can always be advised regarding the logical implication of the preceding data concerning their verbal interactions. A relevant advise is to maintain the input within close range of the child's developmental level providing her or him with language that is semantically rich and pragmatically appropriate but only slightly more complex formally than their own. This may run contrary to the naive belief of well-intentioned parents that more complex input in absolute value should always be facilitative [the kind of belief that presided over the first research works on the topic (e.g., Buium et al., 1974)].
Correctly adapted parental responsiveness has become a central feature of particular intervention curricula designed to address the language but also the cognitive and social needs of young children with developmental problems (including children with DS). One will see for a good case in point the work of Mahoney and associates (e.g., Mahoney, in press; Mahoney, Finger, & Powell, 1985). These researchers have demonstrated the effectiveness of adapted parental responsiveness on several developmental pivotal behaviors in large groups of children with developmental problems.
If the linguistic environment of a child with MR is not problematic, how are we to explain her (his) language difficulties? Recall Harris's (1987) observation that exposed to corresponding language input DS children profit less from the input over the same period of time than their TD counterparts.
Several explanatory perspectives may be considered, acknowledging that the language development of children with MR follows the same steps and sequences of steps and seem to witness the same processes as typical development (of course, with considerable delays and incompleteness; cf. Rondal & Edwards, 1997, for a discussion). A confirmed explanation is not possible yet (logically, if not empirically), as long as the exact determinism of language ontogenesis in TD children is not firmly established.
For lack of experimental evidence, we are still unable to weight the respective influences on language development of possible innate linguistic representations and learning-constructions. Although Chomskyan types of ideas concerning formal and/or functional grammatical categories (Pinker, 1994) are less accepted in the sense that their supposed genetic origins and cerebral underpinnings remain as mysterious as they were when first proposed (Tomasello, 1995; Rondal, 2006a), they can not be completely ruled out on the basis of the available information. Contrastive, modelised and empirically validated, proposals exist under the banner of connexionism (see Rondal, 2006a, for an analysis), suggesting that it is possible to dispense from formal rules and linguistic representations qua representations in language functioning. The relevant paradigm for language learning development in the latter perspective may be implicit learning and memory; a paradigm first explored by Reber (1967) that has been rejuvenated in recent years to accommodate a large number of cognitive and linguistic facts regarding development (cf. Paradis, 2004; Rondal, 2006a).
Within a perspective such as representational nativism (Pinker, 1994), what prevents an individual with MR from developing fully grammatical language in the first place is the lack of preservation or transcription (not clearly established nor perhaps establishable) of the (supposed) genetic blueprint for grammar. In conformity with such a hypothesis, Pinker (1994) proposed that adolescents with Williams Syndrome (a genetically-based disability) may have better morphosyntactic abilities despite their MR because grammatically-relevant genetic information has been preserved. However, Pinker (1994)'s claim that grammar is mostly intact in WS has been falsified in more recent works (cf. Rondal, 2006a).
In an implicit learning perspective applied to mental retardation, the emphasis would be on problems in the learning of language itself. Although current views of implicit learning see it as robust and relatively independent of general cognitive abilities, semantic and overall procedural memorizing, and possibly abstracting from language input towards formal and functional grammatical categories (if these categories are indeed needed to function properly linguistically, which may be questioned; cf. Paradis, 2004; Rondal, 2006a; for discussions regarding this point), may represent particularly difficult tasks for children with MR.
There is also the repeated claim in recent years, that working memory limitations in Baddeley's terms, (1980), particularly regarding the so-called phonological loop (i.e., a subsystem based on verbal items, allowing to refresh the incoming information therefore with a greater chance to have it transferred to longer-term stores) are largely responsible for the difficulties of children with MR in language development (cf. Brock & Jarrod, 2005). As convincing as the data of Jarrod and associates look, it remains that working memory a form of explicit memory, is of limited relevance to implicit learning.
Whichever the final answer to the preceding theoretical interrogations, it is clear that it is the child who is in charge of her or his language development, even if parental input appears facilitative. Interpretable in this direction, are data regarding the feedback question, i.e., the way parents react to children's utterances. Contrary to some proposals in the Eighties (e.g., Moerk, 1983, 1992), no formal teaching motivation or capacity can be reasonably attributed to parents of TD children (and likely also to parents of children with MR) beyond the supply of an appropriate input for language construction. The analyses of parental reactions to children's utterances (cf. Rondal, 1997) show that these reactions are motivated almost exclusively, particularly with younger children, by the veridicality and semantic aspects of the productions. Parental feedback is almost always a response to the semantic and pragmatic aspects of children's speech, but not or much less to its morphosyntactic aspects (given that semantically appropriate but grammatically incorrect utterances may be approved, whereas grammatically correct but semantically or pragmatically inappropriate ones tend to be discarded).
The child is responsible for analysing the input received and inducing the relevant regulatory patterns. A child with MR is at a major disadvantage in this respect, not because of an input that would be ill-adapted, as seen, but because of limitations in devoted psycholinguistic abilities as a result of neuropsychological limitations which have begun to be documented (cf. Wisniewsky, et al, 2006; Rondal, 2006b).
Baddeley, A. (1980). Human memory. Hove, UK: Erlbaum.
Barrett, M., & Diniz, F. (1989). Lexical development in mentally handicapped children. In M. Beveridge, G. Conti-Ramsden & Y. Leudar (Eds.), Language and communication in mentally handicapped people (pp. 3-32). London: Chapman and Hall.
Bernstein, B. (1961). Social class and linguistic development: A theory of social learning. In A. Halsey, J. Floud & C. Anderson (Eds.), Education, economy, and society (pp. 288-324). Glencoe, Il: Free Press.
Bernstein, B. (1964). Elaborated and restricted codes: Their social origins and some consequences. American Anthropologist, 66, 55-69.
Brock, J., & Jarrod, C. (2005). Serial order reconstruction in Down syndrome: Evidence for a selective deficit in verbal short-term memory. Journal of Child Psychology and Psychiatry, 46, 304-316.
Broen, P.(1972). The verbal environment of the language-learning child. American Speech and Hearing Association Monographs, (Whole) No. 17.
Brown, R. (1973). A first language. Cambridge, MA: Harvard University Press.
Buckhalt, J., Rutherford, R., &, Goldberg, K. (1978). Verbal and nonverbal interactions of mothers with their Down's syndrome and nonretarded infants. American Journal of Mental Deficiency, 82, 337-343.
Buium, N., Rynders, J., & Turnure, J. (1974). Early maternal linguistic environment of normal and Down's syndrome language-learning children. American Journal of Mental Deficiency, 1974, 79, 5258.
Cardoso-Martins, C., & Mervis, C. (1985). Maternal speech to prelinguistic children with Down syndrome. American Journal of Mental Deficiency, 89, 451-458.
Cheseldine, S., & McConkey, R. (1979). Parental speech to young Down's syndrome children: An intervention study. American Journal of Mental Deficiency, 83, 612-620.
Compernol-Bredart, C., Rondal, J.A., & Peree, F. (1981).More about maternal and paternal speech to language-learning children in various dyadic and tryadic contexts. International Journal of Psycholinguistics, 8, 149-168.
Cross, T. (1977). Mothers'speech adjustments: The contribution of selected child listener variables. In C. Ferguson & C. Snow (Eds.), Talking to children (pp. 151-188). Cambridge, UK: Cambridge University Press.
Cross, T. (1980). Linguistic feedback and maternal speech. Comparisons of of mothers addressing hearing-impaired children (unpublished manuscript), Melbourne University, Department of Psychology.
Cunningham, C., Reuler, E., Blackwell, J., & Deck, J. (1981). Behavioral and linguistic developments in the interactions of normal and retarded children with their mothers. Child Development, 52, 62-70.
Dolley, D. (1974). Mothers and teachers: Instruction and control patterns observed in interaction of middle-class mothers with trainable mentally retarded and nonretarded children (unpublished report No. 7.32). Bloomington, IN: University of Indiana, Center for Innovation in Teaching the Handicapped.
Furrow, D., Nelson, K., & Benedict, H. (1979). Mothers' speech to children and syntactic development. Journal of Child language, 6, 423-442.
Golinkoff, R., & Ames, G. (1979). A comparison of fathers' and mothers' speech with their young children. Child Development, 50, 28-32.
Gutmann, A., & Rondal, J.A. (1979). Verbal operants in mother's speech to non-retarded and Down's syndrome children matched for linguistic level. American Journal of Mental Deficiency, 83, 446-452.
Harris, S. (1995). The relation of maternal style and the language development of children with Down syndrome. Dissertation Abstracts, 55 (7-A), 1907.
Hooshyar, N. (1986, May). Functional analysis of language interactions between Down syndrome children and their mothers. Paper presented at the 110th Annual Conference of the American Association on Mental deficiency, Denver, CO.
Hooshyar, N. (1987a). Relationship between maternal language parameters and the child's language competency and developmental condition. International Journal of Rehabilitation Research, 10, 321324.
Hooshyar, N. (1987b, April). Communicative interaction between non-handicapped and Down syndrome children and their mothers. Paper presented at the Biennial Meeting of the Society for Research in Child Development, Baltimore, MD.
Jones, O. (1977). Mother-child communication with prelinguistic Down syndrome and normal infants. In R. Schaffer (Ed.), Studies in mother-infant interaction (pp. 126-149).. New York: Academic.
Kogan, K., Wimberger, H., & Bobitt, R. Analysis of mother-child interaction in young mental retardates. Child Development, 1969, 40, 799-812.
Levi, G., & Zollinger, B. (1981). Difficultes dans la communication mere-enfant avec retard mental. Enfance, 4, 289-298.
Mahoney, G. (in press). Cognitive rehabilitation. In J.A. Rondal & A. Rasore-Quartino (Eds.), Therapies and rehabilitation in Down syndrome. Chichester, UK: Wiley.
Mahoney, G., Finger, I., & Powell, A. (1985). The relationship between maternal behavioral style to the developmental status of mentally retarded infants. American Journal of Mental Deficiency, 90, 296302.
Mahoney, G.J. (1975). An ethological approach to delayed language acquisition. American Journal of Mental Deficiency, 80, 139-148.
Mahoney, G.J., & Seely, P. (1976). The role of the social agent in language intervention. In N. Ellis (Ed.), International review of research in mental retardation (Vol. 8, pp. 48-99). New York: Academic.
Marshall, N., Hegrenes, J., & Goldstein, S. Verbal interactions: Mothers and their retarded children versus mothers and their nonretarded children. American Journal of Mental Deficiency, 1973, 77, 415-419.
Martins, C. (1985). Early vocabulary acquisition by Down syndrome children: The roles of cognitive development and maternal language input. Dissertation Abstracts, 45 (8-B), 2712.
Maurer, H., & Sherrod, K. (1987). Context of directives given to young children with Down's syndrome and non-retarded children. American Journal of Mental Deficiency, 91, 579-590.
Mervis, C., & Bertrand, J. (1994). Acquisition of the novel name-nameless category (N3c) principle. Child Development, 65, 1646-1662.
Mervis, C., & Bertrand, J. (1995). Acquisition of the novel-nameless category (N3c) principle by young children who have Down syndrome. American Journal of Mental Retardation, 100, 231-243.
Mitchell, D. (1976). Parent-child interaction in mental handicap. In P. Berry (Ed.), Language and communication in the mentally handicapped (pp. 161-183). London: Arnold.
Moerk, E. (1983). The mother of Eve as a first language teacher. New York: Ablex.
Moerk, E. (1992). Language taught and learned. Baltimore, MD: University Park Press.
Paradis, M. (2004). A neurolinguistic theory of bilingualism. Amsterdam: Benjamins.
Petersen, G, & Sherrod, K; (1982). Relationship of maternal language to language development and language delay of children. American Journal of Mental Deficiency, 86, 391-398.
Pinker, S. (1994). The language instinct.New York: Morrow.
Reber, A. (1967). Implicit-learning of artificial grammars. Journal of Verbal Learning and Verbal Behavior, 6, 855-863.
Rondal, J.A. (1976). Maternal speech to normal and Down's syndrome children matched for mean length of utterance (Doctoral dissertation, University of Minnesota, 1976). Ann Arbor, MI: University Microfilms International.
Rondal, J.A. (1978a). Maternal speech to normal and Down's syndrome children matched for mean length of utterance. In C.E. Meyers (Ed.), Quality of life in severely and profoundly mentally retarded people: Research foundations for improvement, Washington, D.C.: American Association on Mental Deficiency, Monograph n3, pp. 193-265.
Rondal, J.A. (1978b). Patterns of correlations for various language measures in mother-child interactions for normal and Down's syndrome children. Language and Speech, 21, 142-252.
Rondal, J.A. (1980). Father's speech and mother's speech in early language development. Journal of Child Language, 7, 353-369.
Rondal, J.A.(1985). Adult-child interaction and the process of language acquisition. New York: Praeger.
Rondal, J.A.(1997) Interactions verbales adulte-enfant et construction du langage: le probleme de l'information en retour. In J. Bernicot, J. Caron-Pargue, & A. Trognon (Eds.), Conversation, interaction, et fonctionnement cognitif (pp.43-61). Nancy, France : Presses Universitaires de Nancy.
Rondal, J.A. (2002). Aspectos del desarollo lexico en el retraso mental. Revista de Logopedia, Fonioatria y Audiologia, 22, 24-33.
Rondal, J.A. (2006a). Expliquer l'acquisition du langage. Caveats et perspective. Hayen (Sprimont, Belgium) : Mardaga.
Rondal, J.A.(2006b). Language specificity in Down syndrome. In J.A. Rondal & J. Perera (Eds.), Down syndrome. Neurobehavioural specifity (pp.101-123). Chichester, UK: Wiley.
Rondal, J.A., & Edwards, S. (1997). Language in mental retardation. London: Whurr.
Rosenberg, S., & Abbeduto, L. (1993). Language and communication in mental retardation. Development, processes and intervention. Hillsdale, NJ: Erlbaum.
Seitz, S.(1975). Language intervention Changing the language environment of the retarded child. In R. Koch & F. de la Cruz (Eds), Down's syndrome (pp. 157-179). New York : Bruner/Mazel.
Siegel, G. (1963a). Adult verbal behavior in "play therapy" sessions with retarded children. Journal of Speech and Hearing Disorders Monograph,10, 34-38.
Siegel, G. (1963b). Verbal behavior of retarded children assembled with pre-instructed adults. Journal of Speech and Hearing Disorders Monograph,10, 47-53.
Siegel, G. (1963c). Adult verbal behavior with retarded children labelled as "high" or "low" in verbal ability. American Journal of Mental Deficiency, 67, 417-424.
Siegel, G. (1967). Interpersonal approaches to the study of communication disorders. Journal of Speech and Hearing Disorders, 32, 112-120.
Siegel, G., & Harkins, J.(1963). Verbal behavior of adults in two conditions with institutionalized retarded children. Journal of Speech and Hearing Disorders Monograph, 10, 39-46.
Snow, C. (1972). Mothers' speech to children learning language. Child Development, 43, 549-565.
Spradlin, J., & Rosenberg, S.(1964). Complexity of adult verbal behavior in a dyadic situation with retarded children. Journal of Abnormal and Social Psychology, 68, 694-698.
Tomasello, M. 1995). Language is not an instinct. Cognitive Development, 10, 131-156.
Wisniewsky, K., Kida, E., Golabek, A., Rabe, A., Albertini, A., Palminiello, S., & Walus, M. (2006). Down syndrome: From pathology to pathogenesis. In J.A. Rondal & J. Perera (Eds.), Down syndrome. Neurobehavioural specificity (pp. 17-33). Chichester, UK: Wiley.
Author Contact Information :
Jean-Adolphe Rondal, Ph.D.
Department of Cognitive Sciences
Universite de Liege
Laurence Docquier, M.A.
Department of Cognitive Sciences
University of Liege
|Printer friendly Cite/link Email Feedback|
|Author:||Rondal, Jean-Adolphe; Docquier, Laurence|
|Publication:||The Journal of Speech-Language Pathology and Applied Behavior Analysis|
|Date:||Sep 22, 2006|
|Previous Article:||EIBT research after Lovaas (1987): a tale of two studies.|
|Next Article:||Training in phonological awareness generalizes to phonological working memory: a preliminary investigation.|