Language and Communication in Mental Retardation

Development, Processes, and intervention

Sheldon Rosenberg, Leonard Abbeduto

• Publisher: Psychology Press
• Year: 2013
• ISBN:
  9781134743896
• Edition: 1
• Topic: Persönliche Entwicklung
• Subtopic: Schreib- & Präsentationsfähigkeiten

Research on language and communication development and intervention in persons with mental retardation has been conducted at a fast and furious pace during the last two decades. Past attempts to summarize this research have been rather restricted, focusing on a single, narrowly defined substantive domain such as lexical development, or of a single etiology such as Down Syndrome. This volume, in contrast, presents a critical, integrative review of research and theory on language development and processing across all domains and a variety of etiologies. In addition, many previous attempts to review portions of this research have failed to consider the research within the context of current theory and data from developmental psycholinguistics and linguistics. A major contribution of this book is the emphasis on relevant work outside of mental retardation for understanding and treating the language and communication problems of persons with mental retardation. Finally, this book is comprehensive and up-to-date across all the areas of language covered including appropriate introductory material in linguistics and psychology -- discussions of the innateness, cognition-first and motherese views of normal language acquisition. In addition, the authors' extensive bibliography is valuable in and of itself to any serious student or professional in the area.

1

Introduction

In this book, we describe and account for the linguistic and communicative capabilities of persons with mental retardation. As we understand it, mental retardation is a condition characterized by delayed (but not qualitatively different from normal) intellectual growth, as indexed by performance on a standardized test of intelligence. It is a condition, moreover, that appears early in life, tends to persist, has multiple causes, varies in severity, and has implications for the ability of an afflicted person to adjust to the demands of everyday independent living in a world of other people.

Given this picture of mental retardation and the common observation that intelligence includes both nonverbal and verbal components (Horn, 1976), we expect to find that language and communicative development in persons with mental retardation, as compared to chronological age (CA)-matched normal (non-retarded) persons, are characterized by: (a) later onset, (b) slower but not deviant development, (c) lower final level of achievement, and (d) variation in onset, rate of development, and final level of achievement. However, the reader will learn, as we did, that these expectations are not always supported by the available research literature. A lower final level of achievement, for example, is not an inevitable correlate of mental retardation. In other words, our examination of the research literature on language and communication in persons with mental retardation revealed a more complex relationship between mental retardation and development in these domains than one would have anticipated.

To illustrate this fact, we turn to a review of three studies of language functioning in persons with mental retardation. We then attempt to define mental retardation more fully.

Selected Studies

Dooley’s 1976 PhD Dissertation

Dooley (1976) analyzed recorded samples of the spontaneous speech of two home-reared Down syndrome children, Timmy (IQ = 51, MA = 2;51, CA = 3;10 at time of testing) and Sharon (IQ = 44, MA = 2;11, CA = 5;2 at time of testing), at approximately 2-week intervals over a period of 12 months. (Age figures separated by a semicolon refer to years and months.) Down syndrome is a chromosomal disorder (in most cases, the cells of the affected individual contain three number 21 chromosomes instead of the normal two) that is associated with, among other things, mental retardation (Pisarchick, 1987). At the outset of the investigation, Timmy’s CA was 3;9 and Sharon’s was 5;1. Neither child displayed any hearing or speech-articulation problems that might have interfered with performance. The data analyzed by Dooley consisted of the first three (Sample I) and the last three (Sample II) sessions of the 12-month period. The specific measures he examined were computed from the children’s analyzable single and multiword nonimitative utterances. An imitation was considered to be “a partial or complete repetition of any of the preceding five utterances of another speaker” (p. 23).

On a measure found to correlate positively with linguistic maturity in nondisabled preschoolers (Brown, 1973; Miller, 1981)—mean length of utterance (MLU)—both Timmy and Sharon were functioning at what is called Stage I of normal multiword syntactic development (Brown, 1973). Specifically, the MLUs of both children fell between 1 and 2 morphemes. Timmy’s MLUs were 1.48 and 1.75 for Samples I and II, respectively; Sharon’s were 1.84 and 1.73.

For readers with limited backgrounds in linguistics, the morpheme is the smallest linguistic unit that is assigned meaning in a language. Moreover, linguists distinguish between content morphemes (nouns, verbs, adjectives, and some adverbs) and grammatical morphemes (articles, prepositions, auxiliary be, modals such as would and could, tense markers on verbs, and pluralization markers on nouns). Thus, an utterance such as John parked the car consists of five morphemes: John, park, -ed, the, and car. In the main, grammatical morphemes serve to modulate and enrich the meanings of the basic sentence structures in a language (Brown, 1973) and play a fundamental role in sentence grammar (Radford, 1990a).

How do Timmy and Sharon’s MLUs compare with those of nonmentally retarded children? Dooley compared their MLUs with that of Kathryn, a non-disabled child whose spontaneous speech had been studied by L. Bloom (1970). Kathryn’s MLU at 1;9, when the first sample of her spontaneous speech was taken, was 1.32. Six weeks later it was 1.92, whereas 3 months later it was 2.83. Clearly, Kathryn made more progress in 6 weeks than Timmy and Sharon made in a year.

On the basis of data from nondisabled children reported by Miller (1981, pp. 26–27), it is possible to predict, within certain limits, the MLUs of children from their CAs and vice versa. According to these norms, at the outset of Dooley’s study, Timmy’s MLU should have fallen somewhere between 4.09 and 4.40, whereas Sharon’s should have been somewhere between 5.63 and 6.00. Instead, as indicated, Timmy’s MLU was 1.48 and Sharon’s 1.84 in Sample I. Furthermore, in Sample II, Timmy’s MLU increased to only 1.75, whereas Sharon’s actually decreased somewhat to 1.73. In terms of Miller’s norms, Timmy and Sharon’s MLUs for Samples I and II combined were characteristic of nondisabled children whose CAs were 2;0 and 2;1, respectively. Therefore, according to their MLUs, both children (and Sharon to a greater extent than Timmy) appear to have developed language at an appreciably slower rate than their nonmentally retarded CA-matched counterparts. Moreover, it appears that their language development was also slow for their MAs.

During the early stages of normal language acquisition, there is an increase in the use of multiword utterances. Thus, another estimate of the rate of development of language employed by Dooley was the percentage of nonimitated spontaneous productions that were multiword utterances. On this measure, Sharon showed less change from Sample I (38%) to Sample II (41%) than did Timmy (37% to 48%). Dooley reported, however, that over a period of only 1 month (from CA 1;9), Kathryn’s multiword utterances grew from 32% to 54%.

Expressive lexicon (vocabulary) size increased from Sample I to Sample II for both Timmy and Sharon, as did utterance diversity, which was somewhat similar to that of the utterances produced by 3 nondisabled children studied by Brown (1973), whose MLUs and CAs at the time ranged from 1.68 to 2.06 and 1;6 to 2;3, respectively.

The above measures, of course, do not identify the specific linguistic structures that are developing. We turn now to data that do.

During Stage I of language development, nondisabled children (Brown, 1973) make considerable progress in the mastery of the multiword syntactic structures that express semantic relations such as: (a) nomination (e.g., It’s a duck, Me doctor), (b) nonexistence (e.g., No knife, It gone), (c) agent–action (e.g., It spilled, The cat sleeping), (d) entity-locative (e.g., It’s outside, They here), and (e) possessor-possession (e.g., My comb, Baby bed). Dooley found that such structures and relations accounted for a substantial percentage of Timmy’s and Sharon’s multiword utterances in Samples I and II. Indeed, these examples, which look very much like the utterances produced by nondisabled children during Stage I, were actually produced by Sharon (Dooley, 1976, Appendix B.2). Similar examples can be found in Timmy’s protocol. Timmy and Sharon both showed a substantial increase in the relative use of basic semantic relations from Sample I to Sample II, although Timmy’s use of such relations increased to a greater extent than Sharon’s. On this and other measures, then, Dooley’s two Down Syndrome children with mental retardation differed in their rates of language development. Such differences, of course, are also characteristic of nondisabled children (Brown, 1973).

Dooley compared his subjects’ performance on semantic relations with that of a younger nondisabled child, Kendall (Bowerman, 1973), for whom data were available at two different times (CA 1;10 and 1;11). He reported that “Kendall’s growth in one month was approximately half the growth shown over a period of a year by Timmy and Sharon” (Dooley, 1976, p. 88). Moreover, it appears that Timmy and Sharon achieved a level of use of semantic relations not unlike that of the 3 younger (CAs 1;6, 2;3, and 2;3) nondisabled children studied by Brown (1973). Therefore, we have further evidence of delay in the mastery of these relations, although the delay is not as great as that suggested by the comparison with Kendall.

From an examination of cross-linguistic studies of early multiword utterances in nondisabled children, Bowerman (1975) proposed that, in the main, “word order corresponds to the dominant (or only) adult order” (p. 280). In other words, young nondisabled children appear to recognize early the significance of word-order constraints in the local language. Do children with mental retardation show similar sensitivity? The answer, based upon Rosenberg’s (1982) analysis of the multiword utterances of Timmy and Sharon, is yes. According to Rosenberg, both children “appear to have been sensitive to word order constraints in expressing semantic relations in the earliest stage of combinatorial speech” (p. 340).

One of the most thoroughly investigated aspects of language development in English-speaking children is the mastery of grammatical morphemes, 14 of which were made famous by Brown (1973). These grammatical morphemes included the present progressive (-ing), the plural, the uncontractible copula (e.g., Are they nice?), the past regular (-ed), and the third person irregular (e.g., He has or does).

To a considerable extent, an examination of the linguistic and nonlinguistic environments of communication allows one to identify contexts that require a particular grammatical morpheme. Thus, if a person is asked the question “How did John get home last night?” we would find appropriate “He walked,” but not “He walks,” “He will walk,” or “He walking.” Brown (1973) employed 90% correct usage in obligatory contexts as a criterion of grammatical morpheme mastery.

In brief, what Brown and other developmental psycholinguists found regarding the 14 grammatical morphemes is a more or less invariant order of mastery among nondisabled children. What is more, on the average, the process of mastery begins late in Stage I. Given these findings, it was inevitable that Dooley would examine the progress of mastery of the 14 grammatical morphemes in Timmy and Sharon.

According to this investigator, these Stage I children “had not acquired productive usage of any of the 14 grammatical morphemes considered …” (Dooley, 1976, p. 98). Timmy and Sharon’s performance on the 14 grammatical morphemes was comparable to that of Brown’s 3 younger nondisabled children at Stage I, who had also failed to acquire any of these morphemes. However, an examination of the percentage of correct usage in obligatory contexts for these morphemes did not suggest that they were mastering them in an order different from that of Brown’s 3 nondisabled children.

Finally, Timmy and Sharon employed pronouns rather than nouns in the expression of a number of the basic semantic relations (e.g., agent–action), and a substantial proportion of their multiword utterances were syntactically unanalyzed routines or formulas (e.g., multiword utterances such as thank you and say cheese in which at least one of the words does not appear in combination with any other word or words).

Thus, like nondisabled children, Timmy and Sharon produced both pronouns and formulaic utterances; however, as Dooley pointed out, they also employed nouns to express, for example, the agent role in agent–action utterances and displayed productive use of a number of syntactic structures in their word combinations.

In summary, Dooley’s subjects developed the same linguistic structures that nondisabled children develop, albeit at an appreciably slower rate. Moreover, the rate varied with the measure under investigation. In addition, like nondisabled children, Timmy and Sharon differed in the progress they made during Stage I of language acquisition. Finally, none of the findings suggested that the strategies Timmy and Sharon employed in mastering English differed from those employed by nondisabled children whose language development has been studied. In general, then, we found evidence of exceptional delay relative to CA and MA but no evidence of deviance in the language development of Dooley’s 2 children with Down syndrome.

Rosenberg and Abbeduto’s Research on the Linguistic Competence of Adults with Mild Mental Retardation

Rosenberg and Abbeduto’s (1987) investigation differed in a number of respects from Dooley’s:

1. Their subjects were adults (CAs 21 to 31) whose MAs were higher.
2. The subject sample was larger.
3. Although the factors responsible for (i.e., the etiologies of) their mental retardation were unknown, none of Rosenberg and Abbeduto’s subjects appeared to be suffering from Down syndrome.
4. The data consisted of measures of linguistic competence—grammatical morpheme and complex sentence usage (percentage of total number of sentences)—taken from the spontaneous conversations of triads of the subjects.

The focus of the analysis of grammatical morphemes in this study was the 14 items studied by Brown (1973). On average, Rosenberg and Abbeduto’s subjects had reached Brown’s criterion of 90% correct usage in obligatory contexts on all but three of these morphemes. Moreover, a significant positive correlation was found “between mean percent correct usage in obligatory contexts and Brown’s rank order of acquisition” (p. 23) in nondisabled children. Thus, the errors made by the adults with mental retardation on the 14 grammatical morphemes, although quite limited in number, tended to occur on items that young nondisabled children (as well as Dooley’s Down syndrome children) also found difficult. It is possible, therefore, that all such individuals acquire the 14 grammatical morphemes in a similar manner.

Mature complex sentence usage reflects a mastery of grammatical operations that allow one to combine simple sentences. Moreover, complex sentences are complex both syntactically and semantically. It is not surprising, then, that it takes nondisabled children a number of years to master such structures (Bowerman, 1979; Karmiloff-Smith, 1986).

Overall, the largest percentage of complex sentences produced by Rosenberg and Abbeduto’s adults with mental retardation (31.1%) were those composed of three or more simple sentences. Moreover, 28% of their conversational turns contained one or more complex sentences. In addition, these investigators noted that their subjects produced instances of the majority of the complex sentence types in the English language.

The subjects in this study, then, displayed a relatively high level of (if not normal) mastery of complex sentence structures and 14 grammatical morphemes. This group of persons with mental retardation, therefore, may have evidenced little or no delay in language development or, if they were appreciably delayed, were eventually able to catch up to their nondisabled counterparts. In any event, it is clear that mental retardation is not a disorder that necessarily results in a lower than normal level of mastery of an individual’s first language.

In brief, a group of individuals with mental retardation whose MAs were estimated in adulthood at between 8 and 13 years were able to master rather abstract features of language. In other words, their linguistic competence showed more consistency with their MAs than Dooley’s (1976) subjects with Down syndrome. These same subjects, moreover, displayed appreciable mastery of some of the requirements of conversation (Abbeduto & Rosenberg, 1980), including: (a) the mechanics of turn taking, (b) the means for expressing and recognizing such communicative functions as assertations, questions, and directives, (c) topic introduction and maintenance procedures, and (d) the means for making and responding to requests for clarification and more information appropriately.

Curtiss’ Case Studies

Curtiss (1988b; see also Curtiss, 1988a) reported on case studies of 3 children with mental retardation whose grammars appeared to be intact. Curtiss and her associates carried out detailed, in-depth studies of the children’s linguistic (expressive and receptive) and nonlinguistic capabilities. The etiology of the mental retardation was known in only one of the three cases.

The first case Curtiss described was that of a child named Antony who was studied when he was between 6 and 7 years of age. Estimates of his IQ ran from 50 to 56. His MA was reported to be 2;9 when his CA was 5;6. Although he was reported to be developmentally delayed in a variety of areas (according to parental reports), he began speaking at CA 1;0. Curtiss found that Antony made grammatical errors that were typical for his CA. Moreover, his language was phonologically and syntactically well formed and morphologically elaborate. It also included complex sentence structures. Curtiss noted, however, that Antony was considerably deficient in the domain of semantics. This included incorrect word usage and deficiencies in the expression and comprehension of propositions (i.e., ideas) that led to communication failures, although there were areas of conversational communicative competence in which his behavior was appropriate. Thus, within the domain of language, Antony had developed a selective talent for the acquisition of phonology, morphology, and syntax (i.e., grammar).

On a variety of nonlinguistic cognitive tasks (e.g., attention span, drawing, play, classification, logical reasoning), his performance placed him at or below a level comparable to that achieved by nondisabled 2-year-old children. He performed above expectation, however, in one area—auditory verbal short-term memory.

The second case reported by Curtiss was that of a teenager named Marta (also known as Laura; see chapter 5). Estimates of her IQ varied from 41 to 48. Prior to CA 4 to 5 years, Marta was both nonlinguistically and linguistically delayed. Afterwards, however, language became her major area of development and, like Antony, she evidenced a high level of mastery of phonology, morphology, and syntax but a clearly less developed semantic and communicative competence. Furthermore, her overall nonlinguistic cognitive capabilities looked more like those of a preschooler than a teenager.

The third case reported by Curtiss was a 15-year-old boy named Rick who displayed a broad range of developmental difficulties during childhood. There was an indication, moreover, that he had suffered from anoxia (oxygen deprivation) at birth. For most of his years, he was a patient in a state hospital for severely retarded individuals. Although his performance on no...