Millions of adults in the U.S. report that they speak limited English, and English language ability appears linked to multiple dimensions of adult life, such as civic participation and workforce participation and mobility. The US Government Accountability Office (GAO) examined: (1) the trends in the need for and enrollment in federally funded adult English language programs; (2) the nature of federal support for adult English language learning; (3) ways in which states and local public providers have supported English language programs for adults; and (4) federal agencies' plans for research to identify effective approaches to adult English language learning. To conduct this work, GAO analyzed Census and enrollment data and conducted interviews with federal officials within the Departments of Education, Health and Human Services (HHS), and Labor and the National Institute for Literacy (NIFL); semistructured telephone interviews with state adult education officials in 12 states; site visits to 4 states; and reviews of relevant laws and literature. GAO found that the number of adults who speak English less than very well grew by 21.8 percent between 2000 and 2007, to roughly 22 million. The Adult Education State Grant Program, the key federal program for adult English language instruction, reported enrollment of about 1.1 million English language learners in 2007--which had remained relatively stable since 2000. However, most state adult education grantees they contacted reported increased demand. Also, there are many federal programs that allow for adult English language instruction for which national enrollment data are not collected. GAO is recommending that Education work with HHS, Labor, and other agencies as appropriate to develop coordinated approaches for sharing information and planning and conducting research. Eight appendices are included: (1) Scope and Methodology; (2) Education, HHS, and Labor Programs Authorized for Funds to Be Used for Adult English Language Learning; (3) Selected High-Growth and Community-Based Labor Grants That Align with the Limited English Proficiency and Hispanic Worker Initiative; (4) Methods for Providing English Language Instruction among Labor Grantees That We Interviewed; (5) Comments from the Department of Education; (6) Comments from the Department of Health and Human Services; (7) Comments from the Department of Labor; and (8) GAO Contact and Staff Acknowledgments. (Contains 2 tables, 5 figures, and 91 footnotes.)