Our paper illustrates the application of tools developed for the formal modelling of individual inflectional systems (in particular, stem space analysis), to the description of inflection across a dialect group, in this case the transitional area between northern and southern Gallo-Romance varieties, traditionally termed 'Croissant linguistique'. Such tools provide a means of direct and efficient comparison between the paradigmatic distribution of exponents in different speech varieties: in the case of the Croissant, the organisation of roots, desinences and thematic material all indicate consistent subgroupings of varieties. The study demonstrates the practicality and value of such descriptors even in a minority or endangered language context where data may be scarce and highly variable.