One legal system in 24 equally binding languages: The thesis examines whether and to what extent the legal practice of the European Court of Justice complies with the principle of equal treatment of all language versions. This principle may still have been achievable in the early years of the European Community when there were only four official languages of the six founding Member States. Nowadays, however, full compliance has become virtually impossible given the six-fold increase in the number of official languages. The discrepancy between a claimed methodological standard and legal practice creates an unacceptable state of legal uncertainty. The thesis develops proposals for improvement in three areas: in the drafting process of multilingual European Union law, in the interpretation process, and in the linguistic regime of the Union itself.