What This project explores the life and work of Danish linguist Otto Jespersen (1860-1943) - one of the great names of the language sciences in the early twentieth century. My main aim is to offer a more nuanced and more accurate account of Jespersen's construal of progress (fremskridt) as a pivotal property of linguistic evolution and change. The notion of progress - understood as continual or successive changes in the direction of a better version of some object or condition (e.g. some facet of language, communication, social organization) - was a bearing element in Jespersen's work. In the current project, I seek to clarify in what ways and for what reasons this idea played such a central part in Jespersen's thinking - academically and otherwise. Why The project will result in a more accurate understanding of how Jespersen conceptualized evolution, change and progress in language, as well as of the influences, guiding questions and aims of his research programme. It will likewise yield a better understanding of the relationship between Jespersen's theoretical and applied work, its development across time, and its underlying motives and rationales. Finally, the project will shed new light of Jespersen as an engaged researcher, charting the interplay of his linguistic research, political stance and philosophical ideals. How Aiming to cover a totality of sources on Jespersen, I will analyze Jespersen's published works, manuscripts, archival materials and other unpublished texts. The unpublished documents and rare manuscripts held in Det Kongelige Bibliotek and Rigsarkivet (including the archives of the Royal Academy and the University of Copenhagen) are central to this endeavour. I will supplement my Danish archival sources with archives in Sweden (Uppsala; Lund), the UK (SOAS; Reading) and the US (Columbia; NYC Public Library, the archives of the IALA). SSR Through its engagement with Jespersen's work, the project explores what it means to live and communicate in a multilingual world. It may accordingly offer new perspectives on and rejoinders to contemporary language policy and planning (LPP). By creating a better understanding of possibilities and limits of communicative improvement, the results may likewise be useful for promoting a more balanced and more realistic view on the societal effects of contemporary efforts to regulate language. These insights may be beneficial for contemporary attempts to resolve linguistic issues in international communication, language standardization, and education.