In response to the target article by Law, Power, and Quinto-Pozos, I argue that signed and spoken languages share a common core of phonological mental representations, consisting of events (points in time and/or space), features (monadic properties of events), and precedence (a dyadic relation of temporal order between events). In addition to this, signed languages also include dyadic spatial relations between events/points in space and time. Illustrations of the EFPS model for signed phonology are drawn from some simple ASL signs, and an ongoing diachronic change in ASL motorcycle is analyzed using parallel events, partial reduplication, and underspecification.

We explore the role of irregularity in sound change in signed and spoken languages. While all historical phonologists accept some kinds of irregularity in spoken language sound change, a full, rigorous accounting of where and why we find it has been harder to come by. We draw on the foundations of signed language sound change laid by Law, Power, and Quinto-Pozos to address this with a focus on irregularity. We begin to develop concrete parallels to irregularity in spoken language sound change, such as proposals for lexical diffusion. Throughout, we pay heed to where differences in modality do and do not make a difference.

In response to Law et al.’s (2025) target article on signed language change, I discuss two aspects of regularity in sound change: the role of phonemes and the contribution of iconicity. Drawing on work on sound change in spoken languages, I set out some arguments for why linguistics needs to take proper account of signed language change, in order to better understand language dynamics in general. I further argue that signed ~ spoken language dichotomies or arguments from exceptionalism are unlikely to be as helpful as robust hypothesis testing.

In this response to the target article by Law, Power, and Quinto-Pozos, I draw attention to the fact that ‘sound change’ in sign languages does not seem to follow the Neogrammarian regularity principle and that, as a consequence, synchronic phonologies of sign languages do not have productive, obligatory phonological rules (whether allophonic or allomorphic rules). For example, the sound change that introduced aspiration for voiceless stops at the beginning of stressed syllables (when not preceded by /s/) is reflected as a regular, so-called allophonic rule in the synchronic phonological grammar of Modern English. Sign languages do not appear to have such regular allophonic rules or regular allomorphic rules.

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.

In this response to the target article by Law, Power, and Quinto-Pozos, which correctly points out that phonological change is a characteristic of both spoken and signed language, I note that we have more to learn from sign languages. Since sign languages are all very young in comparison to oral languages, linguists have an opportunity to observe phonological change as it occurs. Law et al. do not take into account the winding path of phonological change and the social and structural factors that influence this path. Conditions for such changes can be determined in part by the modality (oral or signed) in each type of language, as I discuss here.

This paper responds to commentaries by several authors on our target article, ‘Bringing signed languages into the study of regular sound change’ (Law et al. 2025a). We provide some additional context on the research program that spurred the target article and draw on several themes discussed in both the target article and commentaries, specifically (i) the affordances and effects of modality in (theories of) language change, (ii) iconicity (and indexicality), (iii) variation and irregularity in language change, and (iv) language transmission. We highlight the methodological advances afforded by new technologies to study phonetic variation in signed languages and advocate for increased attention to the systematic and comparative study of phonetic variation in signed languages as a window into processes of phonetic and phonological change in signed languages.