The effect of online bilingual shared book reading on vocabulary learning for Korean-English bilingual children

Abstract

본 연구는 이중언어 상호작용적 책읽기 중재가 한국어-영어 이중언어 아동들의 어휘학습에 미치는 영향을 알아보고자 하였다. 상호작용적 책읽기 중재는 단일언어 정상발달 아동과 언어발달장애 아동의 어휘학습에 효과적인 방법으로 알려져 있다. 이중언어 아동들의 언어능력은 각 언어의 노출 시기와 상황적 맥락, 모국어와 제2언어 사이의 상호작용 등 다양한 요인들의 영향을 받으며, 이러한 요소들은 이중언어 아동집단내의 높은 변의성에 영향을 미친다. 이러한 이중언어 아동의 특징이 이들을 위한 평가와 중재에 어려움을 증가시키지만 그럼에도 불구하고 이중언어 아동들을 위한 연구기반 중재방법의 필요성은 높아지고 있으며 이에 따른 연구들도 증가하고 있다. 전통적으로는 단일언어 교육과 중재가 지배적이었으나 모국어를 활용하는 이중언어 교육방법의 효과를 뒷받침하는 연구결과들이 증가하고 있다. 이중언어 중재방법은 아동이 가진 모국어와 제2언어의 언어적 자원을 모두 활용할 수 있으며 아동의 제2언어를 촉진할 뿐만 아니라 모국어학습에도 긍정적인 영향을 주기 때문에 이중언어 아동들에게 효과적인 중재방법으로 제시되고 있다. 본 연구에는 4-5세 정상발달과 언어발달장애 한국어-영어 이중언어 아동들 12명이 참여했으며 아동의 언어능력은 한국어, 영어 어휘검사와 부모보고로 평가하였다. 대상자들은 주 2회, 3주, 총 6회기의 이중언어 상호작용적 책읽기 중재에 참여했으며 중재 후 수용어휘, 표현어휘, 정의하기 능력을 한국어, 영어, 개념적 어휘(conceptual vocabulary)검사를 통하여 어휘학습에 대한 중재 효과를 살펴보았다. 두 집단 내 어휘학습 수행력을 비교하고자 윌콕슨 부호-순위 검정을, 두 집단 간 어휘학습 수행력을 비교하고자 맨-휘트니 검정을 사용하여 이중언어 상호작용적 책읽기가 이중언어 아동들의 어휘학습에 미치는 영향을 검증하고자 하였다. 본 연구의 결과, 정상발달 아동들은 한국어와 영어 수용어휘, 표현어휘, 정의하기 사후평가 결과에서 유의하게 높은 수행력을 보였으며 언어발달장애 아동들은 한국어 수용어휘, 영어 수용어휘와 표현어휘에서 유의하게 높은 수행력을 보였다. 효과크기를 살펴보았을 때 두 집단 모두 모든 어휘검사에서 높은 효과가 나타났다. 이는 이중언어 책읽기 방법이 한국어-영어 이중언어 아동들의 어휘 학습에 효과적이었다는 것을 의미한다. 또한 집단간 사후어휘 평가 결과를 살펴보았을 때 모든 어휘검사에서 정상발달 아동들의 수행력이 유의하게 높았다. 즉, 이중언어 책읽기 방법을 통해 언어발달장애 아동들도 어휘를 학습할 수 있었지만 정상발달아동들과 비교했을 때 보다 더딘 학습능력을 보였다. 본 연구의 결과는 이중언어 상호작용적 책읽기 중재가 한국어-영어 이중언어 아동들의 어휘학습에 효과적이며, 언어발달장애 이중언어 아동의 경우 정상발달 아동보다 높은 강도의 중재가 필요할 수 있음을 시사한다. ;Shared book reading is one of the evidence-based methods of supporting children’s vocabulary which provides rich opportunities for children to learn a wider range of words that are not frequently used in everyday life embedded within a story context (Chae & Yim, 2022; Mol et al., 2009; Wasik et al., 2016). Shared book reading interventions have been found to be an effective intervention for vocabulary learning for children with and without language impairment (Marulis & Neuman, 2010; Park & Yim, 2019; Wasik et al., 2016). Bilingual children have different characteristics in comparison to monolingual children that are impacted by a wide range of factors including their home language exposure, interaction between their L1 and L2, and the timing, context and quality of exposure to each language (Phillips & Lonigan, 2014). Due to the effects of these factors, within group variability is a hallmark characteristic of bilingual children that makes it difficult to assess and develop interventions for this population as a group. In spite of these difficulties, the need for evidence-based interventions for this population remains, and there is a growing number of studies that are investigating effective intervention approaches for bilingual children (Duran et al., 2016). Traditionally, monolingual instruction in the majority language has been the standard educational practice. However, the body of evidence supporting the effectiveness of home language and bilingual instruction for typically developing bilingual children (Farver et al., 2009; Lugo-Neris et al., 2010; Méndez et al., 2018; Restrepo et al., 2010) and those with language impairment (Restrepo et al., 2013; Simon-Cereijido & Gutiérrez-Clellen, 2014) is increasing. Findings from several studies suggest that bilingual approaches produce better reading, language, and academic outcomes for bilingual children (Castro et al., 2011; Rolstad et al., 2005). Furthermore, integrating children’s home language in intervention not only has positive effects on improving literacy, and language outcomes, but also helps bilingual children maintain their connection with their families, who often only speak their home language (Anderson, 2012; Wong-Filmore & Snow, 2000). Bridging to L1 techniques are one of the methods used for bilingual instruction. There is emerging evidence supporting the use of bridging to L1 techniques during shared book reading for bilingual children (Mendez et al., 2018; Wood et al., 2018). Bridging to L1 refers to using L1 to support L2 language skills and allows bilingual children to use linguistic resources from both L1 and L2 to support their learning in both languages (Cummins, 1979). However, no study has compared the effect of a bilingual shared book reading intervention for bilingual children with and without language impairment, and most bilingual intervention studies have been conducted for English and Spanish which are typologically very similar compared to English and Korean. Despite the growing number of bilingual children in Korea and a growing body of evidence around bilingual interventions, there have been no studies that have investigated bilingual interventions for Korean-English bilingual children. In light of these findings from previous research, the current study investigated the effect of a bilingual shared book reading intervention on vocabulary learning for Korean-English bilingual children with and without developmental disorder. A total of 12 children aged 4-5 years old who live in Korea, America, Canada, and Belgium participated in this study. Among the 12 children, there were 6 typically developing Korean-English bilingual children and 6 Korean-English bilingual children with developmental language disorder. Conceptual scoring on 4 measures of Korean and English vocabulary along with parental report of language delay were used to assign participants into typically developing and DLD groups. The Mann-Whitney U-test was conducted to confirm group differences before conducting the study. This study involved 6 online sessions of bilingual shared book reading using bridging to L1 techniques based on shared book reading protocols from Kim et al. (2020) and Mendez et al. (2018). Children were assessed on measures of Korean, English, and conceptual receptive vocabulary, expressive vocabulary, and expressive definitions after participating in the intervention. Wilcoxon signed-rank tests were used to compare differences between pre-test and post-test scores on measures of Korean, English, and conceptual vocabulary for children with and without DLD. Effect sizes were calculated in order to determine the magnitude of the effect of the intervention. Mann-Whitney U-tests were conducted to compare differences between groups on post-intervention measures of Korean, English, and conceptual vocabulary. The results of the study are as follows. First, comparison of pre-post test results on measures of Korean vocabulary for children without developmental language disorder (DLD) revealed a statistically significant increase on all three measures of receptive vocabulary, expressive vocabulary, and expressive definitions. Comparison of pre-post test results on measures of English vocabulary for children without DLD revealed a statistically significant increase on all three measures of receptive vocabulary, expressive vocabulary, and expressive definitions. Comparison of pre-post test results on measures of conceptual vocabulary for children without DLD revealed a statistically significant increase on all three measures of receptive vocabulary, expressive vocabulary, and expressive definitions. Examination of the effect sizes on all measures of vocabulary revealed a large effect. Second, comparison of pre-post test results on measures of Korean vocabulary for children with DLD revealed a statistically significant increase on receptive vocabulary, but not for expressive vocabulary, and expressive definitions. Comparison of pre-post test results on measures of English vocabulary for children with DLD revealed a statistically significant increase on receptive vocabulary and expressive vocabulary, but not for expressive definitions. Comparison of pre-post test results on measures of conceptual vocabulary for children with DLD revealed a statistically significant increase on receptive vocabulary and expressive vocabulary, but not for expressive definitions. Examination of the effect sizes on all measures of vocabulary revealed a large effect. Third, comparison of Korean, English, and conceptual vocabulary measures following the intervention for children with and without DLD revealed that children without DLD performed significantly higher on all vocabulary measures compared to children with DLD. Overall, the results of this study suggest that an online bilingual shared book reading intervention using bridging to L1 techniques facilitated vocabulary learning for Korean-English bilingual children with and without developmental language disorder. Typically developing children demonstrated a statistically significant difference between pre-post test scores on all measures of vocabulary, while children with DLD demonstrated a statistically significant difference on Korean receptive vocabulary, and English receptive and expressive vocabulary measures. However, examination of the effect sizes for both groups revealed a large effect on all measures of vocabulary. Differences between the groups were also observed with typically developing children demonstrating significantly higher scores on all measures of vocabulary. In conclusion, this study corroborated findings from previous research that found shared book reading interventions to be an effective method of vocabulary instruction for monolingual children with and without DLD, with typically developing children outperforming those with a language disorder. In addition, this study confirmed that bilingual shared book reading interventions can facilitate vocabulary learning for Korean-English bilingual children, and provides preliminary evidence that bilingual interventions and bridging to L1 techniques may be effective for languages that are typologically and linguistically distant.