Lexical and Morphological Development for English and Russian in a 3-Year-Old Multilingual Child

Processability Theory (PT) adequately describes the developmental stages of L2 learners across languages. To date, little is known whether PT can predict the grammatical development of bilingual and multilingual children. A longitudinal study examined the lexical and morphological development of a child growing up with Russian and English and exposed to Ukrainian using PT from 2;11 to 3;06. The results show a strong correlation between the child’s vocabulary growth and the development of morphological skills, supporting Lexical Functional Grammar. Grammar development in both languages progressed alongside lexical acquisition, indicating the cumulative nature of language development. The study supported Pienemann’s hypothesized sequences in PT, revealing different stages for Russian and English. It suggests that NP agreement precedes VP agreement in the child’s English. However, there was no evidence supporting the acquisition of the S-procedure before the subordinate stage in English. These findings contribute to understanding Russian-English bilingualism in early childhood.