Search Abstracts | Symposia | Slide Sessions | Poster Sessions
Die verwante woord projek: Using HD-tDCS to investigate acquisition of second language Afrikaans
Poster Session A, Friday, September 12, 11:00 am - 12:30 pm, Field House
This poster is part of the Sandbox Series.
Danielle Fahey3, Garrett Goulstone1, Mila Tasseva-Kurktchieva2; 1University of California, Irvine, 2University of South Carolina, 3University of Alabama
Introduction High-definition transcranial direct current stimulation (HD-tDCS) is a non-invasive brain stimulation technique that modulates cortical excitability through low-intensity electrical currents delivered with high spatial precision. HD-tDCS has been used primarily in clinical research, where stimulation to language-relevant areas has shown promise. However, its potential in second language acquisition (L2A) remains underexplored. This sandbox project investigates whether HD-tDCS applied to the left posterior temporal lobe can enhance learning of lexical and grammatical features in a new language. We examine the potential benefits on two central aspects of language learning: (i) implicit versus explicit L2 learning, and (ii) similarity of structures in the L2 to a known language. L2A research distinguishes between explicit grammar learning, involving conscious understanding and application of rules, and implicit learning, where learners acquire grammatical structures incidentally through repeated exposure without formal instruction. While explicit learning tends to benefit rule-based elements, particularly in adult learners, implicit learning is thought to more closely mirror natural language acquisition and is essential for the internalization of complex morphosyntactic patterns. Relatedly, evidence suggests that learners more easily acquire structures that overlap with their first language. Here, we investigate learning generalization of vocabulary and morphosyntax. We teach Afrikaans cognate (i.e., words with similar meaning and form cross-linguistically) and non-cognate vocabulary, along with morphosyntax (i.e., pronouns and plural endings, which each have some similarity to English). Afrikaans pronoun forms differ from English but match in procedure, whereas Afrikaans plural morphosyntax has one overlapping form and one dissimilar form to English, but with lexical phonology determining plural form. Methods Participants are fluent English-speakers with no knowledge of Afrikaans. In the pilot phase, participants learned Afrikaans vocabulary through picture, text, and audio input delivered via an automated program developed in E-Prime software. In the expanded version of the study, participants will be exposed to both lexical and syntactic input, with vocabulary then sentence training. Participants are pseudorandomly assigned to either an active HD-tDCS stimulation group or a sham control group. HD-tDCS is delivered using a 4x1 ring configuration targeting the left posterior temporal lobe, a region linked to lexical-semantic processing. Approximately 30 minutes after the learning phase, participants complete two post-tests: a grammaticality judgment task (which tests (a) subject-pronoun to predicate-number agreement and (b) vocabulary to plural pattern) and a vocabulary recognition task (which tests non-trained cognates). Follow-up testing occurs again at about 2- and 6-weeks post-training. Measures include accuracy and reaction time on within- and between-group factors. Results Preliminary pilot data from 20 participants revealed a significant interaction between cognate status and stimulation (p < .001). Specifically, participants who received HD-tDCS showed greater accuracy and faster reaction times when learning cognates compared to non-cognates, and outperformed the sham group overall. Conclusion Initial results support the effectiveness of HD-tDCS in enhancing second language vocabulary learning, especially for cognates. This ongoing study expands on those findings to investigate long-term effects and grammar acquisition. By integrating HD-tDCS with explicit and implicit learning mechanisms, this work may inform future neurolinguistic approaches to adult language learning and rehabilitation.
Topic Areas: Multilingualism, Language Development/Acquisition