Rwanda-Rundi or West Highlands Kivu is a group of Bantu languages, specifically a dialect continuum, spoken in Central Africa.
Two dialects, Kirundi and Kinyarwanda, have been standardized as the national languages of Burundi and Rwanda respectively.
Propositions have also been made that tones can shift by a metrical or rhythmic structure.
There are many instances in which the two speech varieties of both languages have words that are slightly different.
One has to memorize such differences as "-anga" in Kinyarwanda in contrast to "-anka" in Kirundi (meaning to dislike or hate), because the shift from "g" to "k" is extremely rare, with proof being words like "inka" (cow), "inkono" (pot) and many other words where "nk" is common in both dialects.