This article investigates consonant gemination in late Nineteenth-and early Twentieth-century haketía, a now moribund, regional dialect of Judeo-Spanish spoken in northern Morocco since the late fifteenth century. Some, but not all, consonant clusters arising across a word boundary undergo regressive total assimilation, e.g. [n.n] siudad ninguna 'no city' but [z.n] laz niñas 'the girls'. We present novel descriptive generalizations to show that regressive gemination is sensitive to the degree of sonority distance between the coda and the onset. Evidence of parasitic harmony comes from lateral+consonant clusters, which undergo gemination only if the target and trigger consonants are already similar in some respect. In the framework of Optima...