Reduction of case morphology is not unusual in the history of languages, especially Germanic. What sets Pennsylvania German apart from an otherwise routine process is the fact that two distinct communities are reflecting two distinctly different developments in their case system—one group, the nonsectarians, is linguistically conservative; the other, the sectarians, is innovative. Therefore, it has been suggested that the internal argument for change is not applicable to Pennsylvania German; rather, the linguistic innovation of the sectarians is indicative of external pressure brought about by bilingualism. This paper argues that the reduction in case markings cannot neatly be assigned to one theory or another; instead, it is a combination of factors acting in tandem to bring about change. Data from Ohio, where case markings have been contracted more recently, provide the link, which points to “multiple causation” as the basis for morphological loss. Quantitative and qualitative evidence is presented from sectarian and nonsectarian groups in Pennsylvania and Ohio.