The role of proficiency and working memory in gender and number agreement processing in L1 and L2 Spanish

Most adult learners cannot attain native competence in a second language (L2). Some approaches maintain that L2 learners cannot access features unavailable in L1 after puberty (Hawkins and Franceschina, 2004) and that they process only superficial structures (Clahsen and Felser, 2006), due to a maturationally constrained critical period for L2 acquisition. In contrast, other approaches hold that late learners may acquire all L2 grammatical features (White et al., 2004) and that they may gain complex structural processing (Hopp, 2007). This study aims to test these models and to investigate the role of language proficiency and working memory on adult L2 acquisition. Beginning and intermediate adult English-speaking learners of Spanish and Spanish monolinguals completed a self-paced reading (online) and a grammaticality judgment task (offline) containing sentences with noun–adjective gender/number agreement/disagreement. The results revealed that all participants were highly accurate in the offline task, but only intermediates and Spanish monolinguals showed sensitivity to gender and number violations in the online task. In addition, intermediates with higher working memory were more accurate on some comprehension questions. These findings indicate that adult learners can develop processing patterns qualitatively similar to those of native speakers and that proficiency and working memory influence their acquisition.