This presentation examines the development of movement repetition in American Sign Language (ASL) and its emergence from iconic, depictive strategies into an abstract morphophonological device. While noun–verb pairs have long been analyzed through synchronic accounts of nominalizing reduplication (Supalla & Newport, 1978; Abner, 2013; 2017), such accounts fail to explain the full range of signs that exhibit movement repetition, including those outside the nominal domain. Drawing on diachronic evidence and parallel architecture (Jackendoff, 2002), I propose that movement repetition entered the ASL lexicon through multiple converging pathways. Semantically, repetition arises from the communicative need to distinguish objects and states from their associated actions. Syntactically, pluractionality and relative clause embedding provide environments where repeated actions are reanalyzed as enduring states or referential entities. Phonologically, modality-specific preferences for repeated, restrained movements further promote its conventionalization, even in the absence of iconic motivation. Together, these interacting pressures fostered the development of movement repetition into a morphophonological feature, now pervasive across the ASL lexicon. By situating this development in a diachronic perspective, the study demonstrates how signers recruit an iconic parameter and restructure it into a less iconic parameter. These findings highlight the unique affordances of the visual-gestural modality while contributing to general theories of language emergence and the interplay between form, meaning, and modality in language change.