Book excerpt: This book is, to some extent, a reference work uniting theory and description. It comprises four structured parts: Phonetics, Phonology, Tonology, and Specific African Sound Patterns. By means of concrete examples, the book describes and compares a wide range of basic and current issues and facts that are of utmost relevance for all persons working on language or linguistics as well as in related fields. The book provides core instruments needed and used in the study of phonology and phonological analyses. It discusses modern phonological theories. Phonological issues and processes, such as vowel harmony, assimilation, dissimilation, lenition, as well as fortition are explained. Prosodic topics, such as tone, stress, pitch, and intonation are considered. Issues in tonology include tonological analysis, tonal behaviour and rules. Special attention is given to specific sounds found in African languages.