Study abroad (SA) has long been understood as a major source of foreign language competence for American students. Based on a large-scale, national assessment project, Carroll (1967) named time spent abroad as one of the most potent variables predicting language proficiency. Based on this solid proof claim, researchers have since investigated language learning in SA using diverse methods and adopting a wide variety of theoretical approaches (e.g., DuFon & Churchill, 2006; Freed, 1995). Over time, concern with general proficiency has given way to studies in which particular aspects of language competence (e.g., fluency, vocabulary growth, pragmatics) are scrutinized in separate studies. The results of these investigations generally show that while SA is certainly a productive context for language learning, its outcomes are neither as dramatic nor as equally distributed among students as one might hope they would be.
Language Learning in Study Abroad: Case Histories of Americans in France (2008)