Mbum languages

The Mbum or Kebi-Benue languages are a group of the Mbum–Day branch of the Adamawa languages, spoken in southern Chad, northwestern Central African Republic, northern Cameroon and eastern Nigeria. Their best-known member is Mbum; other languages in the group include Tupuri and Kare [language (Adamawa)|Kare].
They were labeled "G6" in Joseph Greenberg's Adamawa language-family proposal.

Languages

Southern Mbum: Mbum proper, Mbere, Gbete
South West Mbum :
Central Mbum
*Karang: Karang, Nzakambay, Pana, Ngumi, Kare
*Koh: Kuo, Sakpu
Northern Mbum
*Dama–Galke: Dama, Ndai, Mono, Kali
*Tupuri–Mambai: Mangbai, Mundang, Tupuri

In addition, Pondo, Gonge, Tale, Laka, Pam and To are unclassified within Mbum. To is a secret male initiation language of the Gbaya. Dek is purported in some sources but apparently unattested.
La'bi, an esoteric ritual language of male initiation among the Gbaya Kara, the Mbum, and some Sara Laka, is related to Mbum. It has substantial loans from one or more Sara languages. Other initiation languages in the Mbum family are To, Dzel, and Ngarage.