Initial Bilingual Development: One Language or Two?

It is claimed that bilingual children have two separate linguistic systems from early ages. Over the past decades, linguists carried out a number of studies to test the validity of the claim. They explored bilingual children’s code-mixing in correlation with a variety of linguistic elements, such as lexicon, syntax, phonology in different contexts, concluding that bilingual children had separate linguistic system for each language. Although there were certain limitations in these studies, most of their results supported the statement