The proposed presentation is a progress report from a project which is aimed at establishing some phonetic correlates of language dominance in various kinds of bilingual situations. The current object of study is Swedish students starting in classes which prepare for the International Baccalaureate (IB) programme. The IB classes in Sweden are taught in English, except for classes in Swedish and foreign languages. This means that the students are exposed to and speak a good deal more English than previously. The assumption that students will, on the one hand not “damage” their Swedish, and on the other will improve their English simply by attending an English-medium school will be tested. The linguistic background of the students studied will be established. Their English and Swedish proficiency will be tested according to various parameters (vowel quality, the timing of vowels and consonants in VC sequences, vocabulary mobilisation, perceived foreign accent) on arrival at the school, and again after one and three years at the school. The initial recordings have now been made and preliminary results will be reported