In recent years, numerous proposals have been made with the aim of establishing a systematic hierarchy of relationships for languages for special purposes (LSP), and different approaches have been classified in terms of vertical and horizontal models. Recently, however LSP research has moved more and more towards Applied Linguistics and a segregation has emerged between studies focusing on systematic topics and those based on concrete case studies. While studies in applied LSP research have increased, work on systematic approaches has been neglected. The present study follows a different approach, in that instead of segregating the analysis of concrete case studies from the work on systematic approaches, examples from case studies will be used for testing and revising systematic approaches. In this paper we shall first address the question based on these examples of which long established classifications need to be revised, and consider further whether revising and applying classifications is the way to go in LSP research or whether there is a need for a new typology. In the present paper we shall thus be building on and developing the work on structuring LSP in (Roelcke 2014) and on project-specific terminology (Pelikan & Roelcke 2015).