A study used error analysis to examine and compare the English language proficiency and language learning patterns of two native Japanese speakers, aged 15 and 17. Data were elicited verbally from the subjects, with more elicited from the older, and analyzed for error patterns. Results indicate striking similarities in error patterns; however, a comparison using Krashen's natural order for second language acquisition disclosed a clear difference in English competence in favor of the older subject. In addition, comparison of the older subject's language use in an elicitation exercise and a free-discussion exercise tended to support style-shift theory, with the subject attending to discourse cohesiveness in the free-talking task. Areas in which second language instruction for these subjects could be improved are identified. Contains 10 references. (MSE)