Enterprise models provide various abstractions that help with the design of corporate information systems which are in line with a company’s organisation and its long term strategy. At the same time an enterprise model can be instantiated into a corporate knowledge base. Different from other methods for enterprise modelling, MEMO puts special emphasis on modelling languages. The visual languages provide intuitive abstractions for various observers. Against the background of the requirements imposed by enterprise modelling, the paper presents an extensible framework for specialised modelling languages and their reconstruction for an integrated design environment. The languages are defined in metamodels which in turn are instances of a common meta-metamodel. Similar to a technical language, they provide concepts that help with analysing and structuring a domain with respect to a specific task. The languages share common concepts which allow for a tight integration of the various parts of an enterprise model. To give an impression of the language definitions within MEMO, one particular language, the MEMO Organisation Modelling language, is described in more detail.