Within the EU, multilingualism and cultural diversity in the law pose intractable situations. Of course, EU legislation and documents of major importance are translated into the 23 official languages, but the EU legal language and the specific concepts chosen do not always correspond with the respective national legal languages and concepts. 27 Member States interpret the same legal text, each influenced by its own political system, legal tradition, legal language and concepts, and overall legal view. Therefore, EU legislation may be implemented in many different ways. Vice versa, the national law is not translated into the official languages of the EU. Thus, it is very difficult for the EU institutions to compare implementation of EU legislation, or for businesses and citizens to locate relevant cross-national legal information.This study will investigate typical pitfalls of interfacing between different legal systems using the example of the Services Directive 2006/123/EC. The Directive aims to revitalise the single market by facilitating the cross-border provision of services within the EC. The study will focus on Chapter 2 (Administrative Simplification) of the Directive, and its interpretation in Austria, Germany, and Poland. The applicant is Austrian, therefore the Austrian legal drafting guidelines, which contain rules for the transposition of European legal concepts into Austrian legal language, will be critically analysed. Importantly, the study will connect to machine-executable language and draw up the specific requirements in cross-national legal knowledge engineering. Combining methods of comparative law, legal theory, legal informatics and linguistics, the study will contribute to a better understanding of the semantic differences in law, and offer strategies on how to tackle the problem on a theoretical level as well as on the level of knowledge engineering. Legal certainty, accessibility and intelligibility of the law will be the guiding principles.