The comparison of the moribund dialects of Ocracoke Island, North Carolina, and Smith Island, Maryland, demonstrates that valuable insight into the patterning of variation and change in language death can be obtained by investigating moribund varieties of healthy languages. In addition, it is crucial to investigate not only cases of death by linguistic decay (DISSIPATION), but also cases of death by population attrition in which linguistic distinctiveness is maintained or heightened among fewer speakers (CONCENTRATION). The comparative investigation of both types of language death lends insight into the macrolevel socioeconomic and microlevel sociopsychological factors that lead to the maintenance or demise of moribund languages and language varieties, as well as the nature of change in language death. It is demonstrated that change in both concentrating and dissipating varieties is rapid but otherwise indistinct from change in healthy varieties and that unusual patterns of variation and change can be explained by appealing to the social significance of language features.