Bilingualism and Biliteracy in Down Syndrome: Insights From a Case Study.

We present the case study of MB-a bilingual child with Down syndrome (DS) who speaks Russian (first language [L1]) and English (second language [L2]) and has learned to read in two different alphabets with different symbol systems. We demonstrate that, in terms of oral language, MB is as proficient in Russian as English, with a mild advantage for reading in English, her language of formal instruction. MB's L1 abilities were compared with those of 11 Russian-speaking typically developing monolinguals and her L2 abilities to those of 15 English-speaking typically developing monolinguals and six monolingual English-speaking children with DS; each group achieving the same level of word reading ability as MB. We conclude that learning two languages in the presence of a learning difficulty need have no detrimental effect on either a child's language or literacy development.