This chapter reviews research on the phonetic and phonological production patterns of children exposed to two or more languages in early childhood. Much of the research has examined whether bilingual children differ from monolingual children in their production patterns and, when differences have been found, whether such patterns can be explained by language-internal (e.g., the influence of the phonological properties of one language on the other), language-external (e.g., language input or dominance), or other factors (e.g., the developing lexicon). We focus on language-internal influences, also referred to as cross-linguistic interaction, and review models that have been used to account for interaction. Our findings reveal that, while systematic differences between monolingual and bilingual speech exist, the differences are not large and may be explained by multiple factors. The chapter concludes with a discussion of research limitations which include small participant numbers and a predominance of certain language pairs, factors that have hindered attempts to model cross-linguistic interaction.

This chapter provides a thorough, up-to-date review of the literature on the phonetics and phonology of early bilinguals. It pulls together studies from a range of bilingual settings, including bilingual societies and heritage language contexts. While the chapter mostly reviews evidence from adolescent and adult participants, it also makes reference to the child bilingualism literature, where appropriate. The chapter first reviews studies on the accents of early versus late bilinguals, followed by a discussion of the various explanatory accounts for the observed differences between these two groups. Subsequently, the critical significance of early linguistic experience on bilingual speech patterns is considered, with particular reference to the evidence from childhood overhearers and international adoptees. The following sections then review studies comparing simultaneous and early sequential bilinguals, and those exploring the role of language dominance, continued use, the language of the environment in bilinguals’ pronunciation patterns, and the role of sociolinguistic factors in early bilingual speech patterns. The chapter concludes with suggestions for future research.

Differential Object Marking (DOM) is vulnerable to change in heritage speakers of Spanish and heritage speakers of Hindi. DOM is also vulnerable to L1 attrition in Spanish-speaking first-generation immigrants but not in Hindi immigrants. This chapter examines DOM vulnerability in Romanian. The chapter describes the sociolinguistic characteristics of the Romanian-speaking population in the United, followed by a summary of the overall results of the linguistic background questionnaire and the linguistic tasks. The overall results show that, compared to the Spanish and Hindi-speaking populations, the Romanian-speaking population in the United States is far less numerous, yet their Romanian language skills remain relatively strong compared to the other two groups. The accuracy with DOM of the first-generation Romanian immigrants on all linguistic measures did not differ from those of the Romanian speakers in Romania. Just like in the Hindi study, there appears to be no evidence of language change in the homeland nor signs of attrition of this phenomenon in the first-generation adult immigrants sampled in this study. Yet, DOM and accusative clitic doubling (CD) were found to be somewhat vulnerable to omission in heritage speakers, especially in those exposed to English since birth or very early in life (the simultaneous bilinguals).