Growing up bilingual: examining the language input and word segmentation abilities of bilingual infants

Infants’ early language experiences play a critical role on their language development. In this dissertation, I explored the nature of this relationship in a bilingual context. Specifically, I investigated how bilingual caregivers are providing language input to their infants, and how global measures of this bilingual experience affect early word segmentation (i.e., the ability to recognize words in a sentential context). This work is important for understanding the factors that contribute to the developmental trajectory and processing capacities of bilingual infants. In the first part of this dissertation, I assessed research methods for examining the language input to bilingual infants. To do so, I recruited twenty-one French-English bilingual families with a 10-month-old infant from Montréal, Canada. These families completed language interviews and contributed three full-day recordings at home using the LENA (Language Environment Analysis) recording system. Chapter 2 provides support for using the LENA recording system for investigating the language input in bilingual infants, and Chapter 3 shows that caregivers are reliable at describing their infants’ language experience at home. Next, I described the variability in language experiences within bilingual infants, and how these language experiences might affect word segmentation. In Chapter 4, I recruited 8- and 10-month-old infants from monolingual and bilingual homes. Our findings confirm that monolingual infants can segment bisyllabic words in their native language, but not a non-native language. Critically, our findings reveal that some bilingual infants are able to segment bisyllabic words in both of their native languages by 8-months of age. Interestingly, exploratory analyses suggest that infants’ word segmentation skills in our dual-language task are bolstered if they hear more language mixing from their caregivers. In sum, this dissertation contributes to the growing literature that highlights the wide variability in bilingual language experiences, and their effects on early speech processing skills. Indeed, examining the language experiences and skills of bilingual-learning infants provides us with a unique lens for investigating language acquisition and development.