Mental Health & NLP Detecting and measuring depression, loneliness, ADHD, stress, and well-being from language and images on social media and digital platforms. Building equitable models that account for racial and cultural differences. Public Health Using social media and online data for public health surveillance -- tracking COVID-19 discourse, vaccine attitudes, substance use, cardiovascular risk, and health behaviors at population scale. Cross-Cultural AI Studying how language, emotion, and social behavior vary across cultures, platforms, and communities -- from emoji usage to politeness norms to stress expression across the East and West. Conversational AI for Health Interventions Designing culturally aware conversational agents and digital health interventions for health behavior change, integrating patient-generated data into clinical care.