Acknowledgements
I am grateful to M. Gahr, W. Goymann, I. Safari, and N. Baker for
providing valuable information and advice about conducting fieldwork in
Tanzania. I also thank L. Mlawila and N. Gerhard for helping with my
fieldwork. The research was financially supported by the National
Geographic Society (grant number: EC-KOR-44731R-18), the Kawai
Foundation for Sound Technology & Music, and the Japan Society for the
Promotion of Science (JSPS Overseas Research Fellowships).