This study assessed various traits of two Japanese high school students' communicative performance by examining their interaction with native speakers of English while they were visiting the United States as part of a 5-day study tour. The study focused on the kind of student performance that should be considered a successful outcome of school-based communicative learning. For this tour, students had received English lessons four times per week and taken lessons that emphasized communication two to three times per week. Thirty videotaped scenes of the students' interactions with their host families were analyzed from both functional and formal perspectives. Results indicated that classroom learning may have exercised favorable effects on the establishment of interpersonal relationships and helped improve listening comprehension skills. There were few signs of communicative breakdown due to input incomprehensibility. The host father provided a significant amount of conversational support. However, students' language production failed to attain a high level of syntactic development. The study recommends that some kind of pushed output training be incorporated into communication-first classroom teaching to avoid premature fossilization in productive skill development. (Contains 25 references.) (SM)