Bua languages
The Bua languages are a subgroup of the Mbum–Day subgroup of the Savanna languages spoken by fewer than 30,000 people in southern Chad in an area stretching roughly between the Chari River and the Guéra Massif. They were labeled "G13" in Joseph Greenberg's Adamawa language-family proposal. They are ultimately part of the Niger–Congo family, and have exerted a significant influence on Laal. Bua languages have had extensive contact with Chadic languages. Languages. The Bua languages include: The first to note the similarity between Bua and Niellim in print was Gustav Nachtigal, in 1889. Maurice  Gaudefroy-Demombynes added Tunia and "Mana" (possibly an alternate name for Fanian) in 1907, forming a "Groupe Boa". Johannes Lukas (1937) likewise described a "Bua-Gruppe" consisting of Bua, Niellim, and Koke, and in Joseph Greenberg's 1963 classification "The Languages of Africa", the three languages were placed together in the Adamawa subphylum as a group named Adamawa-13. Later, Pairault (1965, 1969) added the more northerly Gula languages, Fanian, Koke, and Bolgo, allowing Samarin (1971) to define roughly the current membership of the Bua languages/Adamawa-13. Palayer later added Noy. A full list of Bua languages from Boyeldieu, et al . (2018:55-56) is given below. Classification. Kastenholz's (2017:2) preliminary classification divides the Bua languages into a Riverine group and an Inland group. Linguistic features. All of these languages are tonal, with distinctive vowel length and nasal vowels in limited contexts. Most of these languages have lost the typical Niger–Congo noun class system (Goula Iro appears to have retained it to some degree.) However, its former presence is betrayed by their quite complicated system of plural formation, combining internal ablaut with changes to final consonants and/or suffixation. Bibliography. Specific languages. See Niellim, Gula Iro for works on those languages