Increasing the language proficiency of incoming Air Force officers -- RAND's study -- Organization of the report -- Background on adult language learning -- Measuring language proficiency -- Categories of difficulty -- The supply of language expertise -- Individual differences among language learners -- Educational programs designed to achieve high levels of proficiency -- After language learning: attrition and maintenance -- Implications -- Survey of Air Force officers -- Survey sample -- Survey content -- Survey results -- Language skills among Air Force officers -- Language learning experiences -- Relationships between language skills and other desirable outcomes -- Mandatory proficiency policies -- Incentives and disincentives for learning a second language -- Open-ended responses -- Conclusions and recommendations -- Conclusions -- Recommendations -- Immediate next steps -- Closing comment -- A. Descriptions of the ILR proficiency levels -- B. List of language flagship programs -- Screenshots of the survey -- Language courses at ROTC detachments -- E. Additional details on "other" and open-ended responses.