Some of Queen's Erasmus partners will teach in the medium of English (for example in the Netherlands and Scandinavia), however for many host universities you will have to be fluent in the language of the host country, at least by the time you come to take examinations.
Except in the case of language students undertaking study placements as part of their degree, it is unlikely that a Queen’s student will be proficient enough to undertake a study programme taught and be examined in a foreign language. It is important that you bear this fact in mind when selecting a destination.
In advance of your placement, you are encouraged to attend the Queen's Language Centre in the Library. Even if your classes will be taught in English, it is a good idea to learn some of the language of your host country to use when socialising or in shops, etc.