How do we characterize language use?

This article addresses the characterization of language use from the perspective of sociolinguistics and language planning. Firstly, it examines the distinction between institutionalized and personalized communications; it also shows the differences between institutional and interpersonal usage, and takes an in-depth look at the relationships between institutional, professional and individual use. It then goes on to analyse the languages in Catalonia from the following perspective: first generically, and then five specific uses. The reflection on this analysis model closes with two conclusions.