<p> This dissertation is focused on analyzing phonological contact between Slavic and non-Slavic languages in southeastern and northeastern Europe, with the particular goal of describing how the social context of language contact interacts with linguistic factors to shape the outcome of contact-induced change. On the basis of case studies drawn from north Russia and the Balkans, it is argued that feature selection &ndash; understood in terms of Mufwene's (2001, 2008) ecological approach to language change &ndash; constitutes the situation-specific optimization of four potentially competing factors: social prestige, phonological groundedness, faithfulness to L1, and mappability to L2. Chapter 1 of the dissertation provides theoretical context for that claim by reviewing the role that phonology has played up to now in the study of language contact and theoretical approaches to modeling the linguistic outcome of language contact. </p><p> A methodological consequence of this proposal is that it is crucial to examine case studies in a way informed by a thorough understanding of the historical and demographic background underlying the specific sociolinguistic dynamics of each case study. Chapter 2 provides an extensive overview of the historical and sociolinguistic background pertinent to the case studies discussed in later chapters. A particular contrast is drawn between the sociolinguistic environment of north Russia, in which Russian has spread at the expense of other languages for the last millennium, and that of the Balkans, which has been characterized by a more multipolar dynamic of multilingualism, in which no single language played a dominant role in the linguistic ecology of the region. </p><p> Chapters 3, 4, and 5 explicate case studies that show how the factors of social prestige, phonological groundedness, faithfulness to L1, and mappability to L2 interact differently depending on the specific sociolinguistic dynamics of each case study. Chapter 3 is dedicated to a case study examining how the Slavic jers behaved in situations of intense language contact, comparing the outcomes in two particularly interesting locales. The northern periphery of Slavic is represented by Novgorod, which is contrasted with Opoja, where the contact language was Albanian. Chapter 4 examines the breakdown of vowel harmony in West Rumelian Turkish, drawing on data from Macedonian and Kosovar Turkish to argue that the loss of grammatically productive harmony in West Rumelian Turkish is due to grammatical imposition from the surrounding Indo-European languages. Chapter 5 examines the emergence of phonemic palatalization of Veps (a Finnic language spoken in northern Russia) and contact-induced readjustments in the distribution of laterals and diphthongs in Albanian and Slavic dialects in northern Albania, Montenegro, and Macedonia. The case studies discussed in chapter 5 illustrate some possible structural outcomes of language contact under conditions of language maintenance in an intensely bilingual (or multilingual) environment. </p><p> Chapter 6 presents conclusions, with a particular focus on showing how the case studies discussed in chapters 3, 4, and 5 exemplify and support the theoretical proposal outlined in chapter 1 and on evaluating the theoretical account presented here with reference to the recent approaches to language contact discussed in chapter 1.</p>