UC San Diego

Though the majority of the world’s population is bilingual, most of the existing research on child language acquisition has focused on monolinguals. Increasingly, research has begun to investigate language acquisition in bilingual contexts, and has found evidence of both similarity to and difference from patterns found in monolingual language acquisition. One evident source of difference in bilingual language acquisition is interaction, where bilinguals’ acquisition of one language affects their acquisition of the other language. Interaction has been shown to occur at multiple levels of linguistic structure (syntactic, phonological, phonetic), and manifests in three different patterns: acceleration, deceleration, and transfer. Acceleration and deceleration refer to the rate at which bilinguals acquire some property relative to monolinguals in the same language. Acceleration occurs when bilinguals acquire some property faster or earlier compared to monolingual peers, whereas deceleration occurs when bilinguals acquire some property later or more slowly than monolingual peers. Transfer refers to bilinguals’ use of a property specific to one language in their other language. While the occurrence of each of these patterns has been demonstrated in bilinguals’ language acquisition, it is not well understood what causes interaction to occur where and how it does. In this dissertation, I propose that frequency of occurrence and linguistic complexity, both features of the input that are known to affect the course of monolingual acquisition, also direct the appearance of interaction in bilinguals’ acquisition of language. I present findings from a series of studies demonstrating that differences between languages in frequency of occurrence and complexity of phonological properties influence bilinguals’ acquisition of aspects of Spanish and English phonotactics in predictable ways. Specifically, greater frequency of occurrence and greater complexity of phonological properties in one language are shown to promote bilinguals’ acquisition of related phonological properties in their other language.