Because of the global spread of English, many countries teach the language as a school subject with the rationale that it is an important international language, i.e. English as an International Language (EIL). Japan is one such country. In Japan, teaching EIL has another objective alongside improving students' ability to use EIL: this is to develop their 'international understanding'. However, what Japanese students learn in their English classes is not EIL but the English language and culture of two particular groups of English native speakers: American and British speakers of English. The same situation is true of pre-service English teacher education programmes. This partial representation of the international profile of English seems often to result in a biased understanding of EIL. To investigate what norms and values student teachers of English hold in relation to the English language, a case study was conducted investigating a one-semester university course in Tokyo that explored the pluralistic nature of English. The purpose of the case study was to gain insights into students' perceptions of English within a teacher education context, and to investigate whether receiving instruction in issues surrounding EIL, particularly the diversity of English and multilingualism in the world, would affect their perceptions of English. The students' initial and unfolding perceptions and the instructional effects were investigated through questionnaires, interviews, classroom observations, teaching materials and students' writing. The findings suggest that whilst the instruction broadened the students' understanding of the global role of English, it did not significantly affect their beliefs about appropriate norms of English for international communication. Based on these findings, I argue in favour of introducing the concept of diversity in English at earlier stages of English language learning in order to improve students' understanding of EIL and their ability to use English for international communication and international understanding.