As the concept of a mother tongue is difficult to define (some candidates speak several languages at a high level, while others have only a limited knowledge of their mother tongue and would prefer to sit the tests in their usual working language), EPSO has thus opted to test the candidates in languages common to a majority of them. This choice is the most faithful representation possible of the actual working environment within the Institutions.

Finally, at the assessment centre the candidates are not assessed on their language skills (apart from the linguists, of course), but on their general competencies (see the competition notice).