Many people attempt to learn a second language. However, second language learning is notoriously difficult to achieve, especially in adulthood, and people often struggle to attain high proficiency. Even when high proficiency is reached, learners face the difficult yet critical task of retaining what they have learned. Understanding how second language learning and retention takes place in the mind and brain is thus desirable, and may lead to evidence-based improvements in language learning and pedagogy. This would have broad impacts, with educational, economic, security and clinical benefits.

This project examined these issues by training healthy young adult native speakers of English on a 'mini-language', specifically a reduced version of the Basque language (a language isolate spoken in northern Spain and southern France). With this approach one can control the amount, type, and timing of language exposure during the acquisition of a real language. Importantly, by reducing the language to a relatively small number of words and simplifying the grammar, participants can achieve high proficiency in just a few days. We trained participants on the Basque mini-language over the course of three days, while scanning their brains with functional Magnetic Resonance Imaging. We tested examined both words and grammar, the two basic components of language. We found that participants indeed learned aspects of the language (especially the words, and some parts of the grammar) to quite high proficiency, and retained much of that knowledge when tested one month later. Moreover, the brain imaging showed just which brain structures are involved in this process (see figure).

This study is distinctive in several ways. In particular, participants in this study learned a real language, albeit a simpler version, from no knowledge at all all the way to reasonably high proficiency. Additionally, the entire course of learning and then retention was examined both behaviorally (how well they learned the language) and in the brain, moreover for different aspects of language. Thus, this project substantially elucidates just how adults learn and retain a second language in the mind and brain.

By shedding light on the process of attaining reasonably high second language proficiency and subsequent language retention, the proposed research may lead to effective evidence-based language learning and teaching approaches. For example, different neurocognitive mechanisms could be targeted for different aspects of language at different points during learning. Such approaches could have significant impacts for education, security, and the economy, areas in which learning a second or subsequent language is often important, and sometimes critical. The data could also have clinical benefits, since targeting different neurocognitive mechanisms for different aspects of language at different time points could lead to advances in language (re)learning therapies in individuals with developmental or acquired disorders (e.g., developmental language disorder, dyslexia, autism, Parkinson's disease, aphasia). The proposed research and follow-up studies may also impact research methodology, since the demonstration of the utility and validity of this experimental approach may open up new avenues of second language research. Finally, the project has helped train several individuals, including two postdoctoral fellows. 

Last Modified: 10/28/2020
Modified by: Michael T Ullman