Investigating the Influence of Age and Language Aptitude on the Implicit and Explicit Knowledge of ESL Learners

Abstract

Learning age and language aptitude have been identified as two of the most important individual difference factors that influence the long-term learning outcomes of second language (L2) learners. Language aptitude, as comprised of a set of cognitive abilities, mediates the negative influence of learning age, and thus helps to make up for a late start in learning an L2 (DeKeyser, 2000). However, in terms of understanding the nature of the interaction of learning age and language aptitude, a consensus has not yet been made. One theoretical postulation that explains the joint effect of learning age and language aptitude makes references to the different learning systems, that is, implicit and explicit learning systems that are involved in L2 learning (Bley-Vroman, 1988). It is hypothesised that language aptitude plays a compensatory role by facilitating the explicit learning system of learners, so that the late learners whose implicit learning system is less active would have a chance to reach a relatively high level of achievement in their L2. A number of studies have been carried out empirically to examine if language aptitude indeed interacts with learning age as postulated above. However, the research findings have been mixed. Some scholars have found that language aptitude is connected with the explicit learning system only (DeKeyser, 2000; DeKeyser, Alfi-Shabtay & Ravid, 2010; Granena & Long, 2013a), while others concluded that language aptitude also plays a role in implicit learning (Abrahamsson & Hylstenstam, 2008; Granena, 2014). These mixed findings call for further research. This study set out to investigate the extent to which age and language aptitude influence long-term L2 learning outcomes, which are explained in terms of a distinction between implicit and explicit knowledge. A battery of tests was employed and validated as measures of implicit L2 knowledge, explicit L2 knowledge and language aptitude. A total number of 20 native speakers (NS) of English and 86 non-native speakers (NNS) whose native language were Mandarin took part in this research. At the time of data collection, all of the NNS had been living in the L2 country (New Zealand) for more than 8 years and had been using English as a medium for study and work throughout this period. Results show that learning age is correlated with implicit L2 knowledge, which shows that age indeed influences the implicit learning system of the NNS. Language aptitude is connected with both implicit and explicit knowledge, showing that language aptitude is probably pertinent to both implicit and explicit learning. These results indicate that a young learning age and a high level of language aptitude are both necessary conditions for developing a high level of implicit L2 knowledge. In other words, a high level of language aptitude is not only advantageous for adult learners, but also for early/child learners of L2.