Keywords: Bilingual Children; Vocabulary Development; Linguistic Input; Language Assessment Approaches.
Although bilingualism has been a long-standing topic of interest for scientists of different disciplines(philosophers, psychologists, linguists), most of our current knowledge is not easily applicable to situations that clinicians and researchers face as a result of a recent increase in immigration. This review analyses recent studies investigating vocabulary development in bilingual preschool children who have been simultaneously exposed to the language of their parents' country and to the language of their host country since birth. This review highlights the characteristics of bilingual development and methodological concerns in the assessment of bilingualism. After a general introduction of bilingual language development, this review focuses on the role of linguistic input in bilingual lexical acquisition and diverse approaches to lexical assessment in simultaneous bilingual preschool children.