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English is the language of instruction at Seisen International School. English as an Additional Language (EAL) support is available for non-native English speakers. Elementary language offerings include Japanese and Spanish. In the IB Diploma Programme, Japanese, Spanish and French are offered as language courses, with options such as Japanese B, Japanese Ab Initio, Spanish B, Spanish Ab Initio, and French B.
Seisen International School does not advertise a formal bilingual teaching program. English is the language of communication, instruction and inclusion for the school community. English as an Additional Language (EAL) support is provided for non-native speakers, and elementary language learning includes Japanese and Spanish. Within the IB Diploma Programme, language options include Japanese, Spanish and French, providing additional language study alongside English instruction.
Immersion programs are not described on Seisen's pages. Language study is offered in Japanese and Spanish at the elementary level, and the IB Diploma Programme provides additional language options (Japanese, Spanish and French) rather than immersion tracks. There is no mention of a dedicated English-plus-another-language immersion program.
Seisen International School is a private Catholic school in Tokyo serving the international community, with a total K–12 population of about 700 students representing over 40 nationalities. Teaching is in English, and the school encourages students to speak English within the school. Seisen describes itself as an International Baccalaureate Continuum school, offering Montessori and the IB Primary Years Programme in Kindergarten, IB PYP in Elementary, IB MYP in Grades 6–10 and the IB Diploma Programme in High School. Facilities on the campus include science labs, a design tech room, music rooms, a drama room, library media centers, a chapel, a gymnasium and a field and tennis courts. Seisen also highlights service and leadership opportunities for students as part of school life.