The indigenous languages of the Northern Kimberley region of Western Australia comprise a single genetic family (Worrorran), with three branches, and extensive multilingualism across them. Languages are understood to have been directly installed in the landscape by ancestral creator figures. On that basis language difference - especially in lexicon - figures as an important aspect of social identity. In the center of the Worrorran region there has been structural convergence due to diffusion across the three branches, but continuing lexical divergence. This indicates that both the multilingualism there and the socioculturally motivated preservation of lexical difference are of longstanding.