In order to understand current views on language development in the bilingual child it is necessary to understand the evolution and development of bilingual studies. Definitions of bilingual development have been shaped in the past and continue to be shaped now by the relative weight assigned to one of many factors involved in bilingual development such as the language component investigated. In the present chapter, we will focus on two major language components that have been at the center of varying lines of research on bilingual development: the development of the bilingual lexicon and the development of bilingual syntax. We will also focus on how theories of lexical and syntactic development in bilinguals have reflected our understanding of linguistic and cognitive processes that take place in the bilingual mind and on how they have shaped our views of language acquisition. Theoretical developments in these two major components have also had important consequences for how we view the emergence of new varieties of language and the societal use of language.
Inquiry into lexical and syntactic development in bilinguals evolved as independent lines of research and to a certain extent they were isolated from each other. It is only in recent times, and partly due to new theoretical developments in linguistic theory (Chomsky 1995, 1998, 2001), that they have begun to be perceived not only as complementary areas of research but as part of a more general line of inquiry that aims at developing a complex and rich model of how languages are represented in the mind of the bilingual speaker.
In this book, we espouse a view of language that assumes the existence of different language components: a lexicon, a phonological component, a syntactic component, and an interpretive component (Chomsky 1995). Regarding the syntactic component, we assume a generativist view of syntax according to which knowledge of syntax involves knowledge of (a) basic syntactic operations that allow the formation of syntactic expressions (Merge, Agree and Move), (b) structural configurations that are crucial in determining the grammaticality of expressions (c-command, relativized minimality), and (c) basic units in the lexicon that are labeled functional features (Ouhalla 1991; Chomsky 1995, 1998, 2001; Muysken 2008).