The present study examines a US Department of Defense (DOD) foreign language program using linear and logistic regression to model foreign language proficiency growth over three time intervals. The analysis demonstrates growth from start to finish for a program involving domestic immersion and study abroad and tests the ability of aptitude and achievement measures to predict that growth for a group of 80 students. The findings suggest that a measure of foreign language aptitude and a measure of quantitative aptitude differentiate learning outcomes for the intensive domestic immersion portion of the program while measures of quantitative aptitude and native language verbal aptitude differentiate later-stage learners on the study abroad portion of the program.