Many people grow up using more than one language, but scientists and technology have not fully considered the wide range of ways that people learn and use language across the lifespan. This project brings together researchers to explore how people differ in their language experiences and abilities, and how those differences shape learning, thinking, and communication. By studying this variation, the project helps build more effective tools for education, health, and technology. A central activity of the project is a national symposium that brings together experts to share new ideas, including advanced statistical techniques and modeling approaches that better reflect the complexity of human language behavior. Other potential benefits include improved learning environments, more accurate assessments, and smarter technologies that benefit people with a broad range of language and cognitive profiles. This project contributes to innovation in artificial intelligence (AI) and translational research. Current language-based AI systems often fail to capture the flexibility and complexity of real-world language use, especially when people shift between different communicative settings. By focusing on individual variation in language processing, the project will provide participants with tools to model neural and behavioral data in ways that improve the scientific accuracy of AI systems. These same approaches also enhance clinical and educational applications, such as the developmen