This paper responds to the target article by Law et al. (2025), who explore whether sign languages undergo regular phonological change similar to regular sound change observed in spoken languages. While they argue that iconicity and transmission patterns may inhibit such change, I propose that sign languages evolve systematically in a way that allows for regular change but in modality-specific ways that obscure it. Evidence of grammaticalization, lexicalization, and phonetic variation in sign languages indicates that both signed and spoken languages undergo the same processes, challenging the notion that regular change is absent. Additionally, I propose an approach that examines regular change through bundles of phonological features in signs that act as phonological environments shaping such change. Future research must integrate historical and online data, computer vision, and concerted studies to uncover whether regular phonological change is specific to modality or to language.
