This dissertation explores dialect diversification in the long-distance New World Plautdietsch speech community. Plautdietsch dialects are traditionally classified as belonging to one of two types: either Chortitza or Molotschna. The traditional dialect classification has recently come under scrutiny because speakers rarely use features exclusive to either type. I propose that variation in vowel production is an alternative way of classifying dialect affiliation. In this project, I analyze both the production of vowels and the production of traditional dialect features used by native Plautdietsch speakers living in North America. This work finds that both the traditional dialect features and the innovations in the vowel system are linked to information about a community's migration history, but the two systems represent different aspects of a community's history. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]