Kresh, also known as Gbaya (an ambiguous name shared with many of the unrelated Gbaya languages) is a Central Sudanic language

Central Sudanic languages

Starostin notes that the poorly attested language Mimi of Decorse is suggestive of Central Sudanic, though he provisionally treats it as an isolate.-References:...

 or dialect cluster of South Sudan

South Sudan

South Sudan , officially the Republic of South Sudan, is a landlocked country located in the Sahel region of northeastern Africa. It is also part of the North Africa UN sub-region. Its current capital is Juba, which is also its largest city; the capital city is planned to be moved to the more...

.

Kresh is dialectically diverse. Blench (in press) recognizes five languages, four of which (Kresh, Gbaya, Woro, and Dongo) Ethnologue counts among eight dialects of Kresh (Naka = Kresh-Boro, Gbaya/Kresh-Ndogo, Gbaya-Ngbongbo = Kresh-Hofra, Gbaya-Gboko, Orlo / Woro, Gbaya-Dara, Dongo) and one of which, Furu

Furu language

Furu is a Central Sudanic language of the Democratic Republic of the Congo. Ethnologue has it as one of the Kara languages, but Blench lists it as a Kresh language.-References:*...

 (Bagero), Ethnologue counts as a separate language and places with the Kara languages

Kara languages

The Kara languages are members of the Central Sudanic language family spoken in the Central African Republic. They are Tar Gula, perhaps a dialect cluster, and a second language which both commonly go under the name Kara...

. They note that the dialects are not mutually intelligible, but that Gbaya-Ndogo is universally understood as a prestige variety

Prestige dialect

In sociolinguistics, prestige describes the level of respect accorded to a language or dialect as compared to that of other languages or dialects in a speech community. The concept of prestige in sociolinguistics is closely related to that of prestige or class within a society...

, and that Naka is also commonly understood as the largest variety.