Very little is known about the use of gesture by children with developmental language disorders (DLDs). This case study of "Lucy", a child aged 4;10 with a DLD, expands on what is known and in particular focuses on a type of idiosyncratic "rhythmic gesture" (RG) not previously reported. A fine-grained qualitative analysis was carried out of video recordings of Lucy in conversation with the first author. This revealed that Lucy's RG was closely integrated in complex ways with her use of other gesture types, speech rhythm, word juncture, syntax, pragmatics, discourse, visual processing and processing demands generally. Indeed, the only satisfactory way to explain it was as a partial byproduct of such interactions. These findings support the theoretical accounts of gesture which see it as just one component of a multimodal, integrated signalling system (e.g. Goldin-Meadow, S. (2000). Beyond words: The importance of gesture to researchers and learners. "Child Development, 71"(1), 231-239), and emergentist accounts of communication impairment which regard compensatory adaptation as integral (e.g. Perkins, M. R. (2007). "Pragmatic Impairment". Cambridge: Cambridge University Press.). (Contains 13 figures, 3 tables, and 2 notes.)