Frontmatter -- Preface -- Contents -- Abbreviations -- List of Tables -- List of Figures -- 1. Introduction -- 2. Languages as Adaptive Systems -- 3. Language Change and Population Structure -- 4. Lexical Diversity across Languages of the World -- 5. Descriptive Factors: Language "Internal" Effects -- 6. Explanatory Factors: Language "External" Effects -- 7. Grouping Factors: Language Families and Areas -- 8. Predicting Lexical Diversity: Statistical Models -- 9. Explaining Diversity: Multiple Factors Interacting -- 10. Further Problems and Caveats -- 11. Conclusions: Universality and Diversity -- 12. Appendix A: Advanced Entropy Estimators -- 13. Appendix B: Multiple Regression Assumptions -- 14. Appendix C: Mixed-effects Regression Assumptions -- Bibliography -- Index