(Stellenbosch : Stellenbosch University, 1997) Boshoff, Hendrik Frans Verwoerd; Coetzer, M. W.; Du Preez, J. A.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
The hypothesis tested in this work, is that a regular discretization of formant space (RDF) can be used for the explanation of vowel categories. It is found that the RDF indeed forms the basis for the cardinal vowels of Daniel Jones, which are used by the International Phonetic Association as universal reference sounds. This basis is used to give a definition of an extended set of acoustic cardinal vowels, which could replace Jones' definition. The mutual relationships among these sounds are elucidated by their replacement in a periodic table of acoustic cardinal vowels. Each cardinal vowel dominates a specific part of formant space. The connection between the acoustic cardinal vowels and the vowels used in various forms of speech is investigated.