Although recent research suggests that gains are made in the acquisition of dialectal features during study abroad, the few studies that have been conducted on this topic in Spanish-speaking contexts have focused primarily on features characteristic of Spain. This article examines the L2 acquisition of phonological features characteristic of Buenos Aires Spanish, [[esh - voiceless palato-alveolar fricative]] and [[ezh - voiced postalveolar fricative]], known as "sheísmo/zheísmo," for example the pronunciation of llave [[voiced palatal fricative]aße] "key" as [[esh - voiceless palato-alveolar fricative]aße] or [[ezh - voiced postalveolar fricative]aße]. Participants include 23 learners of Spanish studying in Buenos Aires, Argentina. More than 4,800 tokens were gathered before, during, and at the end of the semester using sociolinguistic interviews, a reading passage, and a word list. These data were analyzed for the influence of linguistic and social factors using mixed-effects logistic regression (Rbrul; Johnson, 2009). Results suggest that participants approximate nativelike norms of use of these features and that time in country is a statistically significant predictor of patterns of phonological variation.