This study investigated degrees of mutual intelligibility among 3 structurally related languages in South Africa: Sepedi, Sesotho, and Setswana. To compare reading proficiency of mother-tongue speakers who enrolled for freshman courses at the University of Limpopo, 4 reading experimental conditions, in the 3 languages and 1 in a harmonized text, were conducted. Using one-way analyses of variance to explore differential performance of the participants across 4 texts, the results show high degrees of mutual intelligibility across all the language groups. In this connection, the author tentatively projects the possibility of harmonizing the orthographic representations and spelling systems as one of language planning activities toward a standard Sotho--a controversial proposition in the South African language policy and planning debates. In the end, useful recommendations for teaching and learning these languages as a cluster and second additional languages are offered. (Contains 3 tables and 4 figures.)