His linguistic works include "A Comparative Reconstruction of Proto-Nilo-Saharan" (2002), "Reconstructing Proto-Afroasiatic" (1995), and "The Historical Reconstruction of Southern Cushitic Phonology and Vocabulary" (1980).
His linguistic works include "A Comparative Reconstruction of Proto-Nilo-Saharan" (2002). He published also "The Historical Reconstruction of Southern Cushitic Phonology and Vocabulary" (1980).