Research Information System
Language Learning, vol.70, no.1, pp.54-84, 2020 (Journal Indexed in SSCI)
Recent decades have seen an increase in research informing our understanding of
the complex ways in which bilingual development is shaped by biological, cognitive,
and behavioral factors. We investigate the predictors that shape, drive, and constrain
the development of the first language (L1) of bilinguals, focusing on 92 Turkish–
English bilingual adults with a wide range (0–42) of age at onset (AaO).We tested their
productive command of L1 lexical, morphological, and syntactic features, investigating
to what extent background variables relating to AaO, experience, and attitudes toward
the Turkish language and culture predict the relative level of proficiency across these
features. To obtain a comprehensive picture of the interaction of these linguistic and
extralinguistic factors, we employed structural equation modeling. We show that for
speakers with younger AaOs, exposure-related factors are associated with the level
of L1 proficiency they retain as adults; for later bilinguals, exposure-related factors
matter less.