The role of Italian Language Exposure on bilingual toddlers in Italian lexical and grammar skills

Abstract The present dissertation explores bilingual language outcomes in comparison to monolingual peers, investigating the predictive factors which affect language achievements, the parental educational background and the language assessment measurements available. This doctoral thesis is divided in 8 chapters. Specifically, Chapter 1 and Chapter 2 provide an overview of the theoretical frameworks on bilingualism and on language exposure respectively, used in the present dissertation. Chapter 3 provides the methodological approach used throughout this study. Chapter 4 focuses on the main results of this project: with a sample of 107 participants (55 monolinguals and 52 bilinguals aged 33 to 41 months old), monolinguals were found to perform better than bilinguals for all the language measurements. Moreover, bilinguals’ language exposure, calculated with the Italian Language Exposure Questionnaire, adapted from the English Plymouth Language Exposure Questionnaire (Cattani et al., 2014), was predictive of their language outcomes in vocabulary comprehension and production, and in grammar comprehension tasks. Moreover, for each measurement it was found a threshold of Italian language exposure over which bilinguals performed as monolinguals, and it was 47% for MacArthur-Bates CDI, 55% for PinG test while for PCGO it could not be calculated. Therefore, bilingual children who are above those levels of Italian Language Exposure, could be assessed with the standardized tests available for monolinguals. Chapter 5 provides an overview of the role of maternal and paternal education on monolinguals’ and bilinguals’ language outcomes; for monolinguals, maternal education levels had a positive impact on direct measurements of noun production (PinG noun production) and paternal education levels had a positive impact on noun production and total words production (PinG word production and noun production); meanwhile, for bilinguals, maternal and paternal education significantly predicted all the language measurements. Moreover, Chapter 6 explores the existence of a noun bias in Italian language acquisition, for monolinguals and bilinguals. Chapter 7 and 8 present the limitations of the study and conclusions. Overall, this study emphasizes the importance of language exposure and parental education in shaping bilingual language development, offering valuable tools for identifying bilingual children at risk of developmental language disorders (DLD), contributing to more effective early intervention strategies.