Table of contents : Contents Foreword I. The predecessors of the Chuvash in the Volga area II. Oppositions in the Oghuric consonant system (Proto-Turkic and Old Turkic period) III. Oppositions in the WOT/VB vowel system IV. Changes in the Middle Chuvash period Summary Appendix: On the Role of Cheremis in the History of the Chuvash Vocalism Literature Abbreviations Indices