Combined effects of age of onset and input on the development of different grammatical structures: A study of simultaneous and successive bilingual acquisition of French

This study investigates the combined effects of Age of Onset of Acquisition (AOA) and quality and quantity of input on the development of three grammatical structures in French. In a longitudinal and multiple case study including successive (L2) Swedish-French bilingual children (n = 3), simultaneous (2L1) Swedish-French bilingual children (n = 3) and monolingual French children (n = 3), we examine the development of finite verb forms, object pronouns and subject-verb agreement. A distinction is made between structures that are early/late in different modes of acquisition and less/more difficult. The operationalization of quantity and quality of input is based on individual input profiles. The results show that AOA affects the development of less difficult and early grammatical structures whereas AOA has no influence on more difficult structures that are acquired late. An effect of input is found in the 2L1 children, and in some of the L2 children. This effect is most clear with more difficult and late structures.