Solving the actuation problem: Merger and immigration in eastern Pennsylvania

Data from fieldwork and a telephone survey is used to demonstrate that the merger of the vowels in words such ascotandcaught, traditionally considered a defining characteristic of the speech of western Pennsylvania, is well established in the former anthracite mining towns of eastern Pennsylvania. Demographic and linguistic data indicate that the merger arose independently in the anthracite towns as a result of massive in-migration of speakers of Polish and other non-Germanic languages around the turn of the century. Having identified the proximate cause of the merger makes it possible to predict the presence or absence of the merger in various towns using demographic data alone.