Introduction

This chapter introduces the aim, subject, issues, theoretical basis, and methodology of this research. On the Jianghan Plain of Hubei province, China, a place on a boundary area between Mandarin and non-Mandarin Chinese, nonmodal phonations (falsetto and breathy) are used for phonological distinction, and the varieties are uni-, di-, and tri-phonational. The dialects of five counties on this plain, Songzi, Shayang, Gong’an, Shishou, and Jianli, are selected for this study of tone definition and evolution. After outlining the history of the identification and definition of Chinese tones, this part introduces the Multi-Register Four-Level tonal model, the theoretical basis for this study.