Research investigating the effect of study abroad on the development of grammatical accuracy has produced conflicting results. Using corpus linguistics research methods--yet to be used more extensively in SLA research--this study investigated students' acquisition of grammatical accuracy and lexical development during study abroad in China on data from a subgroup of 62 students in a corpus of over 1 million characters of transcribed spoken L2 Chinese produced by 89 American college students who studied in China for a semester or academic year. Results show that the students made significant progress in their accuracy of using the perfective aspect marker [Chinese character omitted]"le"; they used more sophisticated vocabulary; and for the two words that mean "but" in English, they shifted from using the less frequent word [Chinese characters omitted]"keshì" to the more frequent[Chinese characters omitted] "dànshì," towards the native norm. The significance of such research and pedagogical implications are discussed.