This paper is concerned with the analysis of the spoken language of teenagers, taken from a newly developed specialised corpus the British and Taiwanese Teenage Intercultural Communication Corpus (BATTICC). More specifically, the study employs a discourse analytical approach to examine vague language in an intercultural context among a group of British and Taiwanese adolescents, paying particular attention to the three categories of vague expressions: (a) vague categories, (b) approximations and (c) hedging. Initial quantitative analysis is employed to inform further qualitative analysis to identify the pragmatic functions of each type of vague langue. The different use of vague expressions between Taiwanese and British participants will also be presented in detail. The research findings demonstrate the pedagogical merit of the analyses of naturally-occurring discourse and thus help in the design of English courses for adolescent intercultural interaction.