Speech science bridges the gap between cognition and biology, investigating the mechanisms by which the abstract codes of human language are physically realized. The African languages Setswana and Sebirwa are particularly interesting test cases because they are reported to exhibit unusual consonants and consonant combinations, some of which are predicted by linguistic theory not to exist. This research project will investigate the consonant systems of Setswana and Sebirwa, using acoustic, perceptual, aerodynamic, and ultrasound techniques. The unusual sounds will be documented in order to test the accuracy of the general descriptions in the literature. The intellectual merit of the proposed research resides in the collection of new empirical data against which linguistic claims will be tested. The results of this research will have implications for theories of possible inventories of sounds, of the physical articulatory and acoustic bases of sound changes, of the way language is processed, and of the way sounds in sequence interact, both at the physical and cognitive levels.
This project will provide new acoustic and articulatory data for one language with a number of typologically rare features (Setswana), and for a second for which no instrumental data is yet available (Sebirwa). The research will promote cooperation between Georgetown University and the University of Botswana. The research will also have a significant training component for both graduate and undergraduate student, and will contribute to the participation of under-represented groups in science by including several African women as researchers. More broadly, a better understanding of the interaction between the abstract speech code and the physical movements of articulators, in any one language and in languages in general, will lead to better models of language learning and teaching, and improved therapies for speech deficits.