Of all of the African language families, the Chadic languages belonging to the Afroasiatic macro-family are highly internally diverse due to a long history and various scenarios of language contact. This pioneering study explores the development of the sound systems of the 'Central Chadic' languages, a major branch of the Chadic family. Drawing on and comparing field data from about 60 different Central Chadic languages, H. Ekkehard Wolff unpacks the specific phonological principles that underpin the Chadic languages' diverse phonological evolution, arguing that their diversity results to no little extent from historical processes of 'prosodification' of reconstructable segments of the proto-language. The book offers meticulous historical analyses of some 60 words from Proto-Central Chadic, in up to 60 individual modern languages, including both consonants and vowels. Particular emphasis is on tracing the deep-rooted origin and impact of palatalisation and labialisation prosodies within a phonological system that, on its deepest level, recognises only one vowel phoneme */a/.