The present study explores the vocabulary development of bilingual children when neither of their languages has a minority language status. With both languages having high relative prestige, it is possible to address the impact of exposure variables: age of onset, length of exposure, and frequency of exposure (FoE) to both languages. Parents of 40 English-Hebrew bilingual children, from mid-high socio-economic status, completed the vocabulary checklist of the MacArthur-Bates Communicative Development Inventory (CDI) [Fenson et al. 1991. "MacArthur-Bates CDI Words and Sentences." Baltimore, MD: Brookes Publishing], its Hebrew adaptation [Maital et al. 2000. "The Hebrew CDI: Language Specific Properties and Cross-Linguistic Generalizations." "Journal of Child Language" 27: 43-67], and a background questionnaire. Two-thirds of the children showed balanced bilingualism, reflecting the relatively higher prestige of the two languages. FoE emerged as the major exposure variable, other than chronological age that contributes to the maintenance of L1 and acquisition of L2 by bilinguals who are dominant in one of their languages. Analysis of individual data shows how using a bilingual CDI can help identify children who are at risk for Specific Language Impairment, testing both languages and generating provisional bilingual norms, or using conceptual vocabulary with monolingual norms.