Chapter 5 returns to the particular problems that Central Chadic languages pose for straightforward application of the comparative method, based on its peculiar typological features, mainly with regard to its underlying root-and-pattern structure, the effect of prosodies, and the interplay between phonemic and non-phonemic (epenthetic) surface vowels. These are exemplified with a focused comparative perspective on two very closely related languages, namely Lamang and Hdi, to follow the gradual divergence of modern surface forms from common underlying roots.