Brain Stimulation Paired With Structured Language Learning in Adults

This study investigates whether transcranial electrical stimulation (tES) delivered during structured language-learning sessions affects the rate and quality of second-language acquisition in adults. Adults who are learning or planning to learn a new language are randomly assigned in equal numbers to receive either active stimulation or sham (placebo) stimulation while completing structured language-learning content. Participants wear a non-invasive transcranial electrical stimulation headset that delivers a low-level electrical current through electrodes resting on the scalp, targeting cortical regions associated with language. Sessions typically last 20 to 30 minutes and may be completed at home or in person at a participating language program. Language proficiency is measured with a standardized assessment before and after the intervention period, with additional app-derived performance metrics and participant-reported measures collected throughout. A follow-up assessment may be conducted up to 12 months after the intervention ends to evaluate whether any observed effects persist. In this study the device is applied as a learning aid in healthy adults. It is not used to diagnose, treat, cure, or prevent any disease.

Inclusion Criteria: * Adults aged 18 years or older * Able to understand the consent materials and the informed consent process in English, or in another language for which an IRB-approved consent form is available * Willing and able to participate in structured language-learning activities for the duration of the intervention period * Able to provide written informed consent Exclusion Criteria: * History of epilepsy or any seizure disorder * Active skin disease, open wounds, or significant skin irritation at electrode contact sites * Implanted electronic medical devices where stimulation would be contraindicated per device manufacturer guidance or investigator judgment after individual risk assessment * Significant cognitive impairment that would interfere with informed consent or study participation * Any other condition that, in the investigator's judgment, would compromise participant safety or the integrity of the study data