Bilingualism and Literacy Development in Children with Down Syndrome: A Case Study, Traducciones de Inglés Técnico

¡Descarga Bilingualism and Literacy Development in Children with Down Syndrome: A Case Study y más Traducciones en PDF de Inglés Técnico solo en Docsity! Bilingualism and Biliteracy in Down Syndrome: Insights From a Case Study Kelly Burgoyne, Fiona J. Duff, and Margaret J. Snowling Additional article information Abstract We present the case study of MB—a bilingual child with Down syndrome (DS) who speaks Russian (first language [L1]) and English (second language [L2]) and has learned to read in two different alphabets with different symbol systems. We demonstrate that, in terms of oral language, MB is as proficient in Russian as English, with a mild advantage for reading in English, her language of formal instruction. MB's Ll abilities were compared with those of 11 Russianspeaking typically developing monolinguals and her L2 abilities to those of 15 English- speaking typically developing monolinguals and six monolingual English-speaking children with DS; each group achieving the same level of word reading ability as MB. We conclude that learning two languages in the presence of a learning difficulty need have no detrimental effect on either a child's language or literacy development. Keywords: Down syndrome, bilingualism, biliteracy, case study Introduction As the number and visibility of children learning multiple languages in childhood has increased, so too has research interest in the impact of bilingualism on the development of children's linguistic, cognitive, and literacy skills. Bilingual children form a heterogeneous group, and their experiences in terms of how and when they learn their languages, as well as whether they develop literacy skills in a language, are diverse. While some children learn to read and write in their dominant language, others may begin literacy instruction in a language they are still acquiring, while still others may be learning to read in all of their languages (Bialystok, Luk, €: Kwan, 2005). As such, quantifying the impact of bilingualism on literacy development is a complex process. Bilingualism and Literacy Development One important consideration is the influence of bilingualism on the cognitive processes that underpin literacy. Research from both monolingual and bilingual children has highlighted the importance of oral language, phonological awareness, and letter-knowledge for reading development (August £ Shanahan, 2006). Oral language skills, particularly vocabulary, are consistently found to be more limited in bilingual children's individual languages than in monolingual children, and these weaknesses are related to limitations in reading comprehension (Babayigit, 2015; Burgoyne, Whiteley, ££ Hutchinson, 2011; Cobo-Lewis, Pearson, Eilers, Se Umbel, 2002; Melby-Lervág $: Lervág, 2014). However, both phonological awareness (PA) and letter-sound knowledge have been found to develop very similarly in monolingual and bilingual children, and in certain instances bilingual children show superior PA abilities (August dz Shanahan, 2006; Bialystok et al., 2005; Bialystok, Majumder, $ Martin, 2003; Chiappe, Siegel, $ Gottardo, 2002). Furthermore, there is now evidence to suggest that having sufficient knowledge of multiple languages is related to advantages in creativity, cognitive flexibility, attention control, working memory, and broader metalinguistic awareness (Adesope, Lavin, Thompson, € Ungerleider, 2010; Reyes, 2012). Thus, the impact of bilingualism on cognitive development is not uniform and is related to positive, negative, or neutral effects depending on the specific skill being considered. An additional feature of bilingual children's literacy development is the potential impact and transfer of skills from one language to the other. A prominent idea within the area of crosslinguistic transfer contends that children's language skills are underpinned by a central processing system, and it follows that children's abilities in one language should be related to their abilities in the other (Cummins, 1991). Where such transfer effects do exist, they may allow bilingual children to take advantage of skills in one language to support development and learning of literac y skills in their other language. This idea has been central to research that considers which cognitive and linguistic skills are correlated across languages and thereby believed to show transfer. Research into the literacy skills of bilingual children has tended to focus on literacy outcomes for children in their second language (L2), and research on biliteracy—learning to read in two language—is still sparse (August £¿ Shanahan, 2006; Reyes, 2012). Bialystok (1997) found that 4- to 5-year-old bilingual French-English and Chinese-English children showed more advanced understanding of symbolic representation as compared to monolingual children, which was interpreted as a result of exposure to multiple languages and its support of children's metalinguistic understanding. In a study of children in their first year of literacy instruction, Bialystok et al. (2005) examined the phonological awareness and literacy skills of Cantonese- English bilingual, Hebrew-English bilingual, Spanish-English bilingual, and monolingual English children. These specific language pairs allowed for the comparison of effects on literacy when children were learning to read in two alphabetic scripts with the same alphabet (Spanish-English bilinguals), two alphabetic scripts with different alphabets (Hebrew-English), and two languages that used different writing systems. Results suggested that bilingual children learning two alphabetic scripts showed advantages for both phonological awareness and decoding, but these benefits were more limited in Cantonese-English bilingual children, suggesting that the specific characteristics of the language pairs to be learned will influence the extent of cross-language transfer and facilitation. Other research has also suggested that writing systems may place different cognitive demands on readers; therefore, the attributes of children's individual languages are an important consideration in terms of how biliteracy affects cognition (Wang, Perfetti, € Lui, 2005). Bilingual Literacy and Down Syndrome (DS) With these findings as a backdrop, we note that most research has been undertaken on bilingualism in typically developing children. However, a concern continually expressed by teachers and clinicians is whether or not to encourage bilingualism in a child with language or learning difficulties and, even more so, encourage biliteracy. There is currently a dearth of information to inform such clinical decisions. Here, we present the case of MB, a girl with DS who is bilingual and biliterate in Russian (her first language [L1]) and English (L2). There are very few studies of bilingualism in DS, and our description of MB provides the first detailed study of biliteracy development in such a child. We believe that this case is relevant to understanding bilingualism and reading development in atypical populations and has practical implications for parents and practitioners working with multilingual children with intellectual disability. DS is a chromosomal disorder caused by trisomy of chromosome 21 (Wiseman, Alford, Tybulewicz, $: Fisher, 2009) and is one of the most common causes of learning disability. DS is associated with a particular profile of cognitive strengths and weakness, though there is considerable variability in the phenotype. Language development is significantly impaired in DS, with broad deficits across language domains relative to nonverbal ability; grammar is a particular area of difficulty, and verbal short-term memory is particularly impaired (Naess, Melby-Lervág, Hulme, 4 Lyster, 2012). Despite these language difficulties, many children with DS can learn to read. Attainment levels vary widely with some children reading at levels commensurate with chronological age (e.g., Burgoyne et al., 2012; Hulme et al., 2012). Performance on reading and related tasks is, however, typically uneven: Although word reading skills are commonly better than expected given levels of phonological awareness (Lemons 4 Fuchs, 2010) and nonword English but /r/ in Russian). Given the language learning difficulties associated with DS, these inconsistencies might reasonably be considered to pose a challenge. The main aim of the current study was therefore to examine biliteracy in DS through a case study and to investigate the extent to which learning two languages might affect the cognitive profile of such an individual as well as the possible impact on literacy development in each language. We first considered MB's general cognitive and linguistic abilities before turning to examine her reading and related skills in English (L2), the language in which she is receiving formal instruction, and in Russian (L1). Specifically, we addressed the following questions: 1. What is MB's cognitive profile? To address this, we compared her performance on nonverbal and verbal tasks. We also assessed her proficiency in L1 and L2 to judge whether she is a balanced bilingual. 2. What are MB's L2 reading skills and her reading progress? To address this, we monitored MB's L2 reading progress over time. 3. To what extent does bilingualism confer an advantage (or disadvantage) for L2 reading? We compared MB's reading ability to that of two comparison groups matched for word reading: (a) Comparison with a group of monolingual English-speaking typically developing children allowed us to consider whether MB's broader reading skills show the typical pattern for her word reading level or whether, consistent with the typical DS profile, she shows better word reading than nonword reading, phonological awareness, and reading comprehension; (b) Comparison with monolingual English-speaking children with DS allowed us to consider potential effects of bilingualism on phonological awareness and nonword reading skills, relative to peers with DS. 4. Does MB show the same reading profile in L1 (Russian) as in L2 (English)? Relatedly, does she perform better in English (the language of formal literacy instruction) or Russian (given the relatively high consistency and regularity of orthography-to-phonology correspondences in this orthography)? To address this question, we compared MB's reading abilities in English and Russian and compared her L1 reading abilities with those of monolingual Russian-speaking typically developing children. Method Participants MB is a child with DS who is functioning in the moderate to severe range on cognitive tests, with better verbal than nonverbal abilities. Indeed, considering her diagnosis, MB's language skills are well developed. MB was born in Belarus to multilingual parents (Russian-English-Belarusian). The family moved to the United Kingdom when MB was 6 months old. She is a sequential bilingual learner, having acquired Russian as her L1 at home with limited exposure to English until school entry (at age 4). MB's parents read to her in Russian daily and extensively and began teaching her to read words in Russian (using a whole-word strategy) at the age of 30 months. They judged her to be “at ceiling” on Russian sight word reading at school entry. At this point, MB could also read around 20 words in English (also due to instruction at home). All of her formal education had been delivered in English. Background information regarding MB's health, and her language and literacy development, were obtained through a semi-structured interview with her parents. Relevant information is summarized in Table. Table 1 Parental report regarding MB's health and language and literacy development MB's first assessment point for the current study was immediately following a 40-week language and literacy intervention (see Burgoyne et al., 2012), when she was 6 years 11 months (T1). MB was subsequently assessed at age 7 years 9 months (T2), when her performance was compared to that of three monolingual comparison groups matched on word reading ability (described below). MB was assessed again in English at age 9 years 6 months to monitor her progress (T3). There are several issues to consider when comparing children with DS to typically developing comparison groups regarding the choice of matching variable. Matching on nonverbal mental age or language ability results in a comparison group that is much younger in age (e.g., Kay-Raining Bird et al., 2005). The utility of this approach is severely limited and not easily applicable to studies of reading, because the comparison group would have significantly less (or perhaps no) exposure to literacy instruction. By matching the monolingual comparison groups to MB on word reading ability, we are able to examine whether MB shows a similar profile across her reading and language skills, or whether her experience of more than one language has led to a different pattern of strengths and weaknesses. DS Monolingual English Comparison Group This group comprised six English-speaking children with DS who had completed the same intervention (Burgoyne et al., 2012) as MB (M age = 9:05, range = 8:01-10;06). They were matched to MB's word reading ability at Tl using the Early Word Reading (EWR) test from the York Assessment of Reading for Comprehension (YARC). Typically Developing Monolingual English Comparison Group (TDE) Fifteen children from the same school as MB acted as English-speaking monolingual controls. They were a similar age to MB at T2 (M age = 7:07, range = 7,02—7;10) and were matched in word reading ability at T2, using the EWR test. Typically Developing Monolingual Russian Comparison Group (TDR) Eleven children living in Moscow acted as Russian-speaking monolingual controls. They were matched to MB's L1 reading ability at T2 using a Russian word reading test (described below); these children were between 9 and 21 months younger than MB at this test point (M age = 6:05, range = 6:00-7;00). Design We designed the assessment battery to assess the cognitive and linguistic skills that underpin MB's literacy in her L1 (Russian) and L2 (English). We employed a range of standardized (English- only) and bespoke (Russian-English) tests to assess general cognitive ability, vocabulary, and literacy skills. MB was tested at three time points (T1, T2, T3) and at T2 completed tests in both English and Russian. Children in comparison groups were tested at T2 only and completed tests in their spoken language (English or Russian). Appendix S1 in the Supporting Information online provides an overview of the tests completed by each group of participants. Tests of General Cognitive Ability To estimate MB's level of general cognitive ability, which could then be compared to her language and literacy skills, we administered five standardized tests. We used these tasks to consider whether MB's cognitive profile was typical of DS with higher nonverbal than verbal abilities. Nonverbal Skills These skills were assessed using two subtests from the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IIL Wechsler, 2003). For Block Design, children were required to manipulate blocks to copy designs of increasing complexity. For Object Assembly, they arranged jigsaw puzzle pieces of increasing numbers in order to complete pictures. In addition, visualspatial memory was assessed using Block Recall (Working Memory Test Battery for Children [WMTBC]; Pickering $ Gathercole, 2001). The experimenter tapped blocks in sequences that increased in length, and children were asked to copy the sequences exactly. Verbal Memory The Digit Recall and Word Recall subtests of the WMBTC were administered in English to assess verbal short-term memory. Children were required to repeat increasingly longer lists of digits and of words, respectively. Measures of Language Skills To provide an assessment of MB's oral language skills, we used measures of receptive and expressive vocabulary. We chose to focus on vocabulary measures because these are known predictors of reading in children with DS. Two tests assessed MB's English vocabulary. The British Picture Vocabulary Scale (BPVS-III, Dunn, Dunn, Styles, $: Sewell, 2009) assesses receptive vocabulary. Target words are presented verbally and the child is required to point to the corresponding picture from four options. The Expressive Vocabulary subtest from the Clinical Evaluation of Language Fundamentals (CELF-IV; Semel, Wiig, 8 Secord, 2003) requires picture naming. In order to compare MB's English language skills with her Russian language ability, the English test items from the BPVS-III and the CELF-IV were translated into Russian independently by two native speakers of Russian, with all translated targets and distractors checked to ensure they were culturally, linguistically, and age appropriate in Russian. Items were discounted in both languages if translation was considered inappropriate or (in the receptive measure) if the target word in Russian was not deemed distinct from the distractors. Only items that both native speakers considered unambiguous were included in the final assessment. Measures of Literacy Skills In order to enable crosslinguistic comparisons, bespoke literac y tasks with parallel RussianEnglish versions were created. All reading and phonological measures were adapted from those of Schwartz (2006). The Russian tests were used as the benchmark, and English stimuli were selected to be of equivalent difficulty. Every effort was made to maximize matching of stimuli across languages in terms of word class, number of syllables and phonemes, consonant-vowel structure, and word frequency, according to English norms from the Children's Printed Word Database (Masterson, Stuart, Dixon, $: Lovejoy, 2003). Parallel test items for each of the bespoke literacy tasks can be found in Appendixes S2 to S5 in the Supporting Information online. Phonological Awareness (T2) Phonological awareness was assessed using bespoke measures of syllable and phoneme deletion and phoneme isolation. Each correct response received a score of 1 point, giving a total score out of 10 for each test in each language. Syllable deletion: Children were asked to delete five initial and five final syllables from two-syllable words. For each item, children heard the word, repeated its full form, and said the word again without the target syllable. Items were such that a Comparison of MB's performance on matched Russian (testing age = 7,10) and English (testing age = 7,09) tasks What Are MB's L2 Reading Skills and to What Extent Does Bilingualism Affect Reading Development? For an initial evaluation of MB's English reading skills, we considered her age-standardized reading scores over a 2.5-year period (see Table 4). MB's reading accuracy and fluency scores consistently fell in the average range, that is, at the same level as her typically developing peers, even though English is her L2. However, as expected for a child with DS, her reading comprehension scores fell in the low- to below-average range. To benchmark her reading ability against that typically observed among children with DS, we used data from an opportunity sample of 51 children with DS (Burgoyne et al., 2012), assessed at Tl in the present study. This sample (M age = 8:08, range = 6;11-11;09) gained an average raw score on the EWR (max = 30) of 13.41 (SD = 10.47). Despite being the youngest child in the sample (6;11 at that time), MB obtained a raw score of 28 on this same test (equivalent to a standard score of 105). While 91.3% (95% CI = 84.21-96.22) of the DS population represented by this sample were estimated to gain lower scores than MB, the difference between her score and that of the sample mean was not significant (1 = 1.38, p=.17). Table 4 MB's standardized reading scores in English across a 2.5-year period Does Bilingualism Confer an Advantage (or Disadvantage) for L2 Reading? MB's scores on tests of phonological awareness and letter-sound knowledge are shown in the upper rows of Table 5. Although MB could read words as well as the TDE group, and her knowledge of letter sounds was similar, her phonological awareness was less well developed; she scored significantly less well than the TDE group in syllable deletion, and marginally so in phoneme deletion and in phoneme isolation of initial sounds. Her performance on phonological awareness tasks was at the same level as that of the DS comparison group with similar reading skill, suggesting that bilingualism offers no specific advantage or disadvantage in these metalinguistic tasks. Table 5 English performance on tests of literacy skills for MB (score) at T2, compared with that of typically developing monolingual English children and children with Down Syndrome (DS: means, standard deviations), matched to MB on word reading accuracy MBss literacy scores at T2 and the average performance of the DS and TDE comparison groups matched for word reading are given in the lower rows of Table 5 (note that MB was being assessed in her L2 while the comparison groups in L 1). MB's word-level reading did not differ significantly from that of the comparison groups (in line with the matching procedure); her performance on the experimental test of nonword reading was significantly below that of the TDE comparison group but it was statistically equivalent on the standardized test. Her reading comprehension was significantly weaker. When compared with the DS comparison group, there was a trend for MB's nonword reading (on the standardized measure) and reading comprehension to be stronger. Does MB Show the Same Reading Profile in L1 (Russian) as in L2 (English)? To assess MB's Russian reading skills, we considered her performance on the Russian reading measures and compared this to scores achieved on parallel English reading tests (first two columns in Table 6). Though MB knew fewer Russian letter sounds than English letter sounds, MB achieved the same score for word and nonword reading across the Russian and English forms of the tests. Table 6 English and Russian performance for MB (score) at T2, compared with that of typically developing monolingual Russian children (means, standard deviations), matched to MB on word reading accuracy Table 6 further contrasts MB's Russian literacy scores with those of the monolingual TDR comparison group. Although Russian is MB's L1, unlike the comparison group, she did not receive formal reading instruction in this language. Relative to the monolingual Russian typically developing group (Table 6), MB's phonological awareness scores were very similar, but her lettersound knowledge was weaker. As would be expected given the matching criterion, MB performed similarly to the comparison group on the test of word reading; however, her nonword reading scores were significantly lower. To summarize our findings, MB has a learning disability as expected for a child with DS, but her verbal skills are relatively well developed; she is a balanced Russian-English bilingual. MB's performance on literacy tasks was stronger in English than in Russian. It is noteworthy that, consistent with the typical DS reading profile, she had poorer reading comprehension than accuracy in English, and nonword reading was at floor in both languages. However, surprisingly, her phonological awareness was not found to be impaired in Russian. Discussion The current investigation was a case study of MB—a young girl with DS who is bilingual in Russian (L1) and English (L2). Using parallel tasks, we assessed her language and literacy skills in each language. We also evaluated her performance relative to monolingual comparison groups of the same level of word reading. In doing so, we provided the first consideration of both bilingual and biliterate attainments in DS. We focused on comparisons with children matched on word reading ability to determine if MB's profile suggests she learned to read following the typical course or as expected given her language learning impairments. MB's Cognitive Profile MB is functioning at the level of a child with intellectual disability in terms of nonverbal cognitive skills. However, in contrast to what is considered typical for DS, she has well-developed oral language skills even though her receptive vocabulary is weak. While it would be tempting to conclude that bilingualism has conferred an advantage for MB's language development, the fact that she was performing similarly to monolingual children with DS who were matched for reading level does not support this hypothesis. MB's L2 Reading Skills and Reading Progress MB provides an exceptional example of reading performance in DS. Word-level reading in her L2—a language to which she was only fully exposed from school entry (age 4) —was consistently at age-expected levels on standardized tests over a 2.5-year period (as good as that of typically developing peers reading in their L1). Although word reading is a relative strength in DS, it is uncommon for it to be in line with chronological age (Groen et al., 2006). Indeed, Hulme et al. (2012) reported that this level was only reached by 8% of children with DS who were included in their longitudinal study of L1 literacy development. Consistent with this finding, when compared at Tl to an opportunity sample of 51 children with DS reading in their first and only language (Burgoyne et al., 2012), MB's word reading in her L2 was at a level better than 91% of the sample, despite MB being the youngest child. Thus, this case study also aligns with that of Groen et al. (2006) in demonstrating that competent levels of word reading can be achieved in children with DS. Another similarity was that MB's reading comprehension was not in step with word reading accuracy, but fell in the low- to below-average range. Thus, MB shows a “poor comprehender” reading profile—a typical outcome for children with DS who achieve good levels of word reading (Groen et al., 2006; Nash : Heath, 2011). Bilingualism Advantage for L2 Reading We now tum to consider whether there was any indication that MB's Russian-English bilingual background had impacted her reading and related skills in either language. Although the findings of a case study cannot be used to attribute causal significance, they can be instructive in highlighting possible associations between bilingualism and reading where there are differences from normal expectation. First, in the comparison with English typically developing readers, we sought evidence as to whether MB showed the typical DS cognitive profile. As expected, she showed low levels of nonverbal ability and vocabulary knowledge relative to the TDE group; however, her verbal memory skills were better developed. This is not the typical DS profile, which suggests that she has better than usual verbal memory abilities. While it is tempting to argue that this is a consequence of bilingualism, the fact that she showed no difference in performance from that of the DS comparison group, who were also good readers, argues against this. When compared with this group, MB showed no advantage on any of the language and general cognitive ability measures. Turning to MB's reading, despite being equated with the typically developing English comparison group on word reading, her strengths and weaknesses in related tasks were typical for a child with DS; she showed weaknesses in phonological awareness, nonword reading (though differences were not significant on the standardized measure), and reading comprehension. Importantly, although bilingualism is thought to confer an advantage on tasks tapping such skills, there was no evidence of an advantage for phonological awareness tasks or for nonword reading relative to monolingual DS readers of similar levels of word reading. Moreover, the finding that MB performed like the monolingual children with DS on the reading comprehension measure suggests that this weakness was associated with DS and not a consequence of bilingualism, which is often the case. Thus, as for oral language, there was no strong evidence that bilingualism confers any advantage or disadvantage in DS. Reading Profiles in L1 and L2 Having seen that MB's oral language was at a similar level in L1 (language of home—Russian) and L2 (language of school —English), we were interested in comparing her reading and related skills across languages. Despite knowing fewer Russian letters, MB could read parallel sets of single words equally well in both languages. When compared with Russian children of similar word reading, MB showed a disadvantage in letter-sound knowledge (perhaps because she had not been taught these explicitly), and her nonword reading skills were poorly developed, despite showing comparable levels of performance in phonological awareness tasks. In summary, when evaluating MB's performance in L1 and L2, the benefits of formal instruction in English were seen in her word-reading skills. However, in neither language did nonword decoding keep pace with word-level reading skills. Arguably, nonword reading in Russian should be relatively easy given the transparency of the language. The fact that MB's deficit transcends orthographies suggests that it is associated with the language profile of DS and is not orthography specific. On the other hand, MB appears to be relatively better at phonological awareness tasks in Russian (relative to the typically developing comparison group) than in English. This is particularly striking because the phonological awareness tasks in English require operations that