The Bilingual Acquisition of English and Mandarin: Chinese Childr ...

the ability of bilingual children to differentiate their languages. Such an orientation involves two related assumptions (Deuchar & Quay, 2000, p. 8): (a) that language separation in the input is necessary in order for bilinguals to separate the languages and (b) that language separation in the input may be achieved only by one parent’s speaking one language while the other speaks the other language. But language separation may occur in many different ways; for example, according to the situation in the home versus outside the home, it could be manifest in the form of one context, one language or one topic, one language, as in my study. Furthermore, researchers do not know whether language separation in the input is actually necessary. García (1983) investigated Spanish-English bilingual preschoolers who heard both English and Spanish from their mothers in speech addressed to them. The incidence of mixed utterances used by the children was quite low (range: 1–15%), and the children were able to use both Spanish and English as separate systems. García’s study shows that the lack of complete adherence to a one parent/person, one language input condition does not necessarily lead to the child’s failure to communicate effectively using two linguistic systems. Furthermore, adults set different standards to which bilingual children are exposed—for instance, code-switched input used together with monolingual input in the child’s environment. These different “adult standards” do not necessarily incur language mixing. Researchers in bilingual children’s acquisition still do not know what degree of language separation in the input is needed for a bilingual-to-be child to differentiate the two languages. Lanza argued: