Do immigrant children profit from heritage language proficiencies?
The debate on effects of bi- and multilingualism is highly controversial, particularly when migrants’ heritage languages are involved. In this controversy Cummins’ interdependence hypothesis plays a major part. It assumes that knowledge, being achieved during first language acquisition, can be transferred during the acquisition process of further languages. This article is based on data that addresses the question of transfer from the heritage language of Turkish-German immigrant children to German as their second language. Additional data also provides results from children with Russian and Vietnamese heritage language. The study concentrates on children at an age when they usually enter the German education system (kindergarten or school). Structural equation modeling is used to examine cross-linguistic transfer in a cross-lagged panel design. Analyses show significant but small cross-lagged effects indicating that oral narrative proficiencies in the heritage language can predict parts of the change in proficiencies in German. Uncertainty about the findings remains due to evidence of unexplained third variable influence. The results call for more precision in the theoretical specification of conditions that regulate direction and amount of transfer outcomes.