Chapter 4 describes the fundamental research questions, empirical approaches and findings of language typology, a linguistic subdiscipline studying language from a cross-linguistic perspective. For analysing the languages of the world comparatively in search for structural commonalities (universals) and differences (scope of variation), methodological issues include considerations on the basis of comparison, sampling, and data sources. Typological findings are finally interpreted in terms of their motivations. The chapter ends with recommendations for further reading and a list of short exercises and ideas for small research projects.