The Kuku language, also called Kutuk na Kuku (Kuku language) belongs to the Karo language group, of the Southeastern Nilotic branch of the Nilotic language family of the Southern Sudan and Northern Uganda. There is no standardized writing system for Kuku; it is sometimes written using the alphabet of a related language such as Bari or Kakwa, with the addition of characters to represent sounds that are not present in the other language. For example, the Bari alphabet can be adjusted for use in Kuku by adding the digraphs gb and kp to represent the voiced and voiceless labiovelar stops, respectively.