PROJECT SUMMARY Asian American immigrants have been particularly vulnerable to health disparities and mental health conditions during the COVID-19 pandemic in comparison to other racial/ethnic groups. There are multiple reasons: a language barrier, its impacts on isolation and marginalization, and anti-Asian hate crime and incidents. In the proposal, we will focus on the detailed component of a language barrier (language proficiency and language identity), and its effect on mental health disparities. Most of the Asian/Asian American immigrants begin using English as an additional language (L2) once they arrive in the U.S., after mainly using a first language (L1) from their parent's country of origin. 1.5 generation Asian/Asian American immigrant young adults—those who migrated to the U.S. with their parents (1st generation) from Asian countries when they were children aged between 5 and 17, have been living in the U.S. at least 2 years, and current ages are between 18 and 25—are a significant health disparity population. However, little research to date has examined how learning an L2 among 1.5 generation Asian/Asian American immigrant young adults informs their sense of acceptance, inclusion, and identity as well as their acculturation, socialization, and psychological well-being in American society. To close this research gap, the objective of the proposed work is to investigate the association between learning an L2 and mental health disparities among 1.5 generation young adults from Asian ethnic groups/Asian Americans as health disparity populations. The central hypothesis of this study is that for socioeconomically diverse 1.5 generation Asian/Asian American immigrant young adults, those who grew up affiliating with one culture and now may also need to affiliate with a new dominant American culture, are more likely to experience psychosocial adversity and mental health disparities. This project has two specific aims, using a mixed-methods research design. First, using quantitative analysis, we will determine the extent to which perceived language proficiency/language identity in 1.5 generation Asian/Asian American young adults is associated with psychological well-being and mental health (Aim 1). Second, using qualitative analysis, we will gain an in-depth understanding of experiences with acculturation and discrimination and how these experiences relate to their perceptions of language skills and psychological well-being/mental health disparities (Aim 2). Data from the study will be the foundation for the development of Asian immigrant-tailored psychological health strategies for successful acculturation in American society associated with learning an L2 that has not been substantially discussed. The project carries practical implications for promoting the design and implementation of multi- sectoral interventions to address the structural drivers of health disparities (e.g., racism and discrimination). In addition, it will bring attention...