The U.S. government encourages the study of critical languages spoken in geographic areas of strategic importance to U.S. national security and the global economy through a variety of discretionary grants and scholarship programs. U.S. students are traditionally underrepresented in the study of these languages; however, many of the nation's K-12 English learners (ELs) enter U.S. schools already speaking these critical languages as home or heritage languages. A federally funded consensus study reported that without school or home support, attrition of these home languages can occur as soon as 12 months after exposure to the dominant language. This fact sheet provides the following data on ELs and critical languages over the 2018-2019 school year: (1) Number and Percentage of Identified English Learners Who Spoke a Critical Language: School Year 2018-19; (2) Percentage of English Learners Who Spoke a Critical Language: School Year 2018-19; (3) Percentage of Identified English Learners Who Spoke the Top Four Critical Languages: School Years 2010-11 to 2018-19; and (4) States with the Highest Percentage of Identified English Learners Who Spoke a Critical Language: School Year 2018-19.