This research proposal aims to investigate the diversification of the reconstructed stage of Proto-West Germanic as it appears in the South Germanic, Frisian, and Pre-Old English runic corpora. To this end, the inscriptions will be phonologically and morphologically analysed, and grouped based on shared features. Dialects and their isoglosses will be drawn up and interrelated to the reconstructed Proto-West Germanic predecessor and its later manuscript-attested daughter languages. Issues surrounding the Ingvaeonic/non-Ingvaeonic division, the status of some dialects as ‘transitional’ or ‘conservative’, as well as the suggested merger of the Frisian and Pre-Old English corpora will be dealt with. In addition, difficult inscriptions whose text and meaning have hitherto been left unresolved will be physically and theoretically re-examined in light of the defined dialect groups. Uniquely, these objects and dialects will be mapped out digitally using GIS-software with the further goal of visualising the isoglosses and, thus, testing this method’s applicability on a smaller corpus of runic inscriptions. The complete findings will be published in a monograph, although the re-assessments of the difficult inscriptions and other findings will also be published in articles during the grant period.