Guide to the reader
Table of Contents.
1. First stage
2. Second stage
3. Third stage
4. Fourth stage
I. Schleicher’s fable in other proto-languages
II. Laryngeal loss and vocalism
III. The three-dorsal theory
    III.1. Introduction
    III.2. In support of two series of velars
    III.3. In support of three series of velars
    III.4. Conclusion.