Educating dual language learners (DLLs) and English learners (ELs) effectively is a national challenge with consequences both for individuals and for American society. Despite their linguistic, cognitive, and social potential, many ELs--who account for more than 9 percent of enrollment in grades K-12 in U.S. schools--are struggling to meet the requirements for academic success, and their prospects for success in postsecondary education and in the workforce are jeopardized as a result. A defining characteristic of DLLs/ELs is their demographic diversity. They are members of every major racial/ethnic group and include both U.S.- and foreign-born youth. Most come from Latin America and Asia, with Mexico being their leading country of origin. They speak a wide range of languages, including Spanish, Korean, Chinese, Fulani, and French Creole, as well as other languages spoken in Europe, Asia, and other parts of the world. Relative to other U.S. children, DLLs/ELs are far more likely to live in poverty and in two-parent families with low levels of education. At the same time, DLLs/ELs have assets that may serve them well in their education and future careers. Those who become proficient in both a home or primary language ("L1") and English ("L2") are likely to reap benefits in cognitive, social, and emotional development and may also be protected from brain decline at older ages. In addition, the cultures, languages, and experiences of ELs are highly diverse and constitute assets for their development, as well as for the nation (Conclusion 3-1). This report addresses both the assets that DLLs/ELs bring to their education and the factors that support or may impede their educational success. (author abstract)