This study investigates the relationship between acculturation and language learning during a year-long study abroad program at the pre-collegiate level. The researcher presents the experiences of four U.S. American sojourners to Sweden as case studies. This mixed-methods study looks specifically at students with no prior knowledge of the target language. The researcher compared descriptions of students' acculturation and a measure of their acculturative outcomes to their language development as measured by an unofficial Oral Proficiency Interview after 5 and 10 months. The results indicated that higher levels of acculturation are associated with higher levels of proficiency, while a rejection of the host culture is associated with lower levels of proficiency. The researcher presents the implications for study abroad program designs that support language learning. (Contains 8 notes and 3 tables.)