Age differences in first language attrition : A maturational constraints perspective

Abstract: This thesis investigates age-related differences in first language (L1) attrition in a second language (L2) setting. The thesis is based on four individual studies. The aim of each of the studies has been to examine aspects of age differences that to date have remained in the background of attrition research: Study I gives an overview of research on age differences in L1 attrition and suggests a reinterpretation of age effects in attrition, using as a point of departure critical period constructs. Study I also formulates hypotheses regarding the contour and timing of attrition susceptibility and its interplay with non-biological factors. Study II investigates L1 residual knowledge and L2 ultimate attainment in international adoptees. The results suggest that a) that L1 remnants may be found if relearning activities have taken place prior to testing; b) L2 learners who have experienced a complete cut-off in L1 contact do not attain higher L2 proficiency levels than learners who have stayed in contact with the L1. The results also indicate that the level of L1 reactivation and L2 ultimate attainment are related to age of adoption. Study III examines age effects on the retention of L1 event construal patterns. The results show that the onset of puberty is a turning point for the degree of conformity with native behaviour, i.e. those who arrived in the L2 setting before puberty were more likely to exhibit non-converging patterns than those who arrived after puberty. This finding suggests that in attrition conceptual proficiency is equally affected by age as are formal language skills. Finally, Study IV explores the role of language aptitude in prepubescent attriters. The results show that nativelike grammatical intuitions are connected to language aptitude, and that speakers with high levels of language aptitude rely less on L1 contact than do speakers with low levels of language aptitude in their retention of nativelike grammatical intuitions in the L1.