- Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 978-0-631-19815-4.
- Based on data from about 400 languages, the book describes the known contrasting phonetic categories, the ways in which the phonemic sounds may differ in human languages.
- Maddieson, Ian, Patterns of Sounds,