His research interests cover formal phonological theory, phonetics, speech processing, and the interface between these research areas. In terms of phonological theory, he focuses on phonological variation, and on how current constraint-based models of phonological grammar (Optimality Theory and Harmonic Grammar) can be adapted to account for variable phenomena. A particular focus of this research is on how to combine grammatical and non-grammatical factors that contribute to variation into one integrated model. His phonetic research has focused on the acoustic description of Southern African languages (both Afrikaans and Bantu languages). He also collaborates with colleagues in the department on topics related to speech perception, with a focus on how phonological grammar impacts speech perception and processing.