In international schools, all teachers contribute to the students' acquisition of English. However, even with that support in regular classes, not everyone comes to the International School of Berne with sufficient background in English to allow an easy transition to a full academic course of study in that language. For such students the English Dept. offers a special ESL (English as a Second Language) programme. Temporarily replacing the study of either French or German (or, if necessary, both languages), ESL offers an intensive exposure to English grammar, vocabulary, syntax, spelling and pronunciation, and it also provides students with a regular opportunity for language assistance as needed in their other subjects of study.

Students join the ESL programme as the result of entry examination scores and/or the recommendation of the Head of English. They can exit ESL at the end of any term when the recommendation of the ESL teacher and/or test scores indicate that this additional formal support is no longer needed.