Linguistically and Culturally Diverse Students: Their Language Development, Assessment, and Support in the Public Education System
Keywords: education policy
heritage language education
immigrant students
language assessment
language development
linguistically and culturally diverse students

This dissertation centers on the experiences of linguistically and culturally diverse (LCD) students in the K–12 public education system, with a specific emphasis on their language development and assessment. Historically, education systems have been designed to accommodate students from mainstream culture who speak the socially dominant language as their first language. However, recognizing the heterogeneous and complex multicultural backgrounds within the LCD student population, it is crucial to provide them with the necessary attention and support to thrive academically and in their lives. This dissertation comprises three empirical research studies conducted in Ontario, Canada, known for its cultural diversity and substantial immigrant population. By examining the experiences and outcomes of the growing LCD student population in the public school system, the dissertation aimed to inform the development of effective policies and practices to enhance their educational experiences and success. In Study 1, the focus was on the development of multilingual identities among LCD students over time and its relationship with literacy achievement in school. By analyzing population-level cohort data, the study tracked the home language environments and English literacy performance of students between grades 3 and 10. A comparison was made between students from multilingual homes and those from English-dominant homes. The findings revealed a rapid shift towards English within student homes, yet also highlighted the benefits of maintaining home languages. Multilingual students who maintained their linguistic diversity exhibited superior literacy performance, emphasizing the positive impact of multilingual competence. Building on the literacy achievement patterns of LCD students established in Study 1, Study 2 investigated the extent to which items on a large-scale reading test provide equitable opportunities for LCD students to demonstrate their learning. The study identified reading test items that assumed a high level of knowledge of mainstream Canadian culture and conducted a multi-group differential item functioning analysis across student groups with varying lengths of residence in Canada. Test items with high cultural sensitivity exhibited differential functioning, disadvantaging LCD students when compared to their Canadian-born English-first-language peers. The findings underscore the need for improvements in test construction to ensure fairness for LCD students. Study 3 evaluated the support provided for the heritage language development of LCD students. This study was designed as a case study of Korean language classes in a publicly funded heritage language program in Ontario, with a focus on assessment and reporting practices. By capturing the perspectives of teachers and parents through individual interviews, Study 3 provided valuable insights and practical suggestions to enhance the assessment practices within Korean classes and improve the overall quality of the heritage language program. Collectively, the three studies shed light on equity-related issues and the support received by LCD students within the school system. The findings have important implications for education policymakers seeking to address the needs of this diverse student population. Policymakers are urged to develop a deep understanding of the heterogeneity within the LCD student population and the fluid nature of their characteristics, formulate comprehensive policies that address their holistic needs, and place a stronger emphasis on policy implementation during the policy design phase. By incorporating these recommendations, policymakers can work towards creating an inclusive and supportive educational environment for LCD students in the K–12 education system.