The Kalenjin cluster comprises at least eight mutually distinct Southern Nilotic languages spoken across the Rift Valley highlands: Nandi, Kipsigis, Tugen, Elgeyo (Keiyo), Marakwet, Pokot, Sabaot, and the critically endangered Terik. Some classifications include Okiek, the language of Kalenjin-speaking forest hunter-gatherers.

Kalenjin languages are renowned for their complex verbal morphology, age-set (ipinda) naming systems, and circumcision initiation songs. The initiatory register uses archaic vocabulary not found in everyday speech.