The development of inflexional case systems has long been of interest to historical linguists. Languages such as Latin, Ancient Greek, and many other Indo-European varieties have lost morphological case distinctions through time. Cross-linguistically, however, we find quite different changes affecting case systems. For instance, Finnish has largely maintained the case system reconstructed for proto-Finnic, whereas the related variety Veps has innovated novel inflexional case-markers.

Although much work has been done to explain the changes that are found in individual varieties, a cross-linguistic comparison of the types of development that are found - that is, the loss, maintenance, or propagation of inflexional case systems - which aims to understand why these particular changes occur has yet to be attempted. This study offers a comparison of several varieties from two unrelated languages families: Italic (Latin and the Romance languages) and Finnic. An understanding of the different morphological structures found in these varieties and how these structures are exploited by language-users in the production of novel inflected forms offers insight not only into what can happen in an inflexional case system diachronically, but why case systems have developed in different ways. Reference to a broader range of languages confirms that there is an implicational relationship between the types of morphological structure found in a language and the size of the inflexional case system.