ABSTRACT: This study investigated the relationship between writing performance and speaking performance through quantitative analysis of the variance and correlation among oral, written, and explicit rule abilities as evidenced in present-tense verbal morphology and syntax. Subjects performed an explicit rule grammar test and a narration task in speaking and writing modes. The operating hypotheses were (1) oral abilities and written abilities differ significantly; (2) oral abilities and written abilities are not strongly correlated; (3) explicit rule knowledge is not a predictor of how well learners can speak or write in the target language. The extent to which the data supported these hypotheses is discussed; concrete pedagogical implications for task ordering, assessment, and explicit rule testing are outlined.