Child heritage speakers’ reading skills in the majority language and exposure to the heritage language support morphosyntactic prediction in speech

Abstract We examined the morphosyntactic prediction ability of child heritage speakers and the role of reading skills and language experience in predictive processing. Using visual world eye-tracking, we focused on predictive use of case-marking cues in Turkish with monolingual (N = 49, M AGE = 83 months) and heritage children, who were early bilinguals of Turkish and Dutch (N = 30, M AGE = 90 months). We found quantitative differences in the magnitude of the prediction ability of monolingual and heritage children; however, their overall prediction ability was on par. The heritage speakers’ prediction ability was facilitated by their reading skills in Dutch, but not in Turkish, as well as by their heritage language exposure, but not by engagement in literacy activities. These findings emphasize the facilitatory role of reading skills and spoken language experience in predictive processing. This study is the first to show that in a developing bilingual mind, effects of reading on prediction can take place across modalities and across languages.