A case study of second language development in a college student focused on comparative changes in the development of oral and written skills over a period of two years. The subject was a Russian student of English as a second language who had recently arrived in the United States. Errors and syntactic maturity were analyzed in writing samples during this period, and compared with results of oral interviews used for placement. Results indicate that errors decreased and syntactic maturity increased in the same way that occurs in a first language. It is believed that time was a critical factor in self-monitoring, so errors would decrease faster in writing when more time was available. However, errors decreased in the subject's oral expression at a faster rate than in his writing, supporting the hypothesis that adults use the language monitoring function to a greater degree than do younger students. Contains 12 references. (MSE)