High school students studying French as a second language in Toronto were administered a questionnaire and a variety of achievement tests in French. Results were analyzed to determine the effects of learner characteristics on the development of second language competence. Four factors in learning success were posited: attitude, strategy, aptitude, and field independence. Aptitude consistently accounted for the largest portion of the variance in achievement. Only certain strategies were found to be responsible for achievement, the chief of which was functional practice. The most critical component of the attitude factor in terms of its effect on achievement was emotional intensity. Field independence was not found to be significantly related to achievement. These findings are taken into account in the revision of a model of language learning processes, which is viewed as having pedagogical implications. (JB)