A multiple baselines approach to studying age, education, and exposure effects in heritage Spanish: What can differential object marking tell us?

This study proposes a multiple baselines approach to better understand the effects of bilingual education on child heritage language (HL) acquisition. Ninety-one child and adult heritage speakers (HSs) of Spanish completed production and selection tasks evaluating differential object marking (DOM) with proper nouns. This study posits that adult HSs are a developmental baseline for child HSs, as they represent the mature bilingual morphosyntactic system. In addition, late elementary school children (ages 10–11) were the age baseline for middle school children (ages 12–14); children monolingually educated in English were the educational baseline for peers with dual language bilingual education (DLBE). The role of individual frequency of HL use was also evaluated. Children with bilingual education produced and selected DOM more than monolingually educated peers, and middle school children did so more than late elementary children. Older children with DLBE matched adult HSs on both tasks. All groups selected DOM more than they produced it. Bilingual education and use of Spanish accounted for individual differences in production more than selection. This study demonstrates that HSs can serve as baselines for one another to better understand education and age effects in the rate and route of HL morphosyntactic development. Results are presented in line with a bilingual alignment approach and implications for DLBE and future HL research are discussed.