Sequential structure and diachronic assimilation in signed languages

Abstract Assimilatory processes are generally understood to rely on sequential structure: a target element adopts features of a preceding or following element. While signed languages arguably show less sequential structure than spoken languages, there are several areas of the grammar of signed languages where sequential structure is evident and the conditions for assimilatory processes are available. Previous work has explored coarticulatory effects in sign production and has identified assimilation in contexts of multimorphemic compounds. This paper extends the investigation of diachronic assimilation to sign-internal assimilation within monomorphemic signs. We present case studies of diachronic assimilation using historical documentation of American Sign Language as well as comparative data from across the so-called French sign language family. We argue that although opportunities for sequentially structured assimilation in signed languages may be significantly fewer than in spoken languages, nevertheless many of the same kinds of assimilatory processes can be seen in diachronic changes to signs.