Wilhelm Bleek (1857/1858) is often mentioned as the first author to have coined the word ‘Ban-ntu’ to refer to Bantu languages. It should however be clarified that this word was not invented by him. He (at least) deserves to be acknowledged as the first known linguist to have used this term to refer to African languages of this large family. The word ‘Bantu’ is indeed used in several Bantu languages to refer to people or human beings. Ba-ntu is the plural of mu-ntu (= a human being). All Bantu languages do not exactly have these two terms. It is however worth remarking that instead of “Bantu” other languages of the Bantu family use cognate words such as wa-tu (Swahili), Ba-to (Lingala), Ba-tho (Setswana), aBa-ndu (Kinyarwanda), A-ba-ntu (iSiZulu), Va-nhu (Shona), etc. to refer to the same concept of human beings.
In the reconstructed Proto-Bantu form, ba- is the plural noun class prefix categorizing "people/human beings" and the root -ntʊ̀ refers to "some/any entity" regardless of whether it is human or non human (e.g. Čilubà/Tshilubà mu-ntu (human being), ci-ntu/tshi-ntu (thing), ka-ntu aku (that small thing/ that small person), ku-ntu aku (that place near where you are), Bleek's use of the term Bantu languages to refer to the ethnolinguistic phylum was inspired by the anthropological observation that Bantu language speaking groups usually identify themselves as "people" or "the true people" (as is indeed the case, for example, with the term Khoekhoe, which is really a kare "praise address" and not an ethnic name.)
The class 2 prefix ba- specifically refers to people and is used to pluralize class 1 prefixed nouns. Names of cultural objects, including languages are formed with the class 7 prefix ki- as in Kiswahili "coast language and culture" isi- (as in Nguni and isiZulu "Zulu language and culture".
Bad memories of the apartheid system which prevailed in South Africa from 1948 to the early 1990s lead some South African linguists into suggesting the replacement of the term “BaNtu” languages” with that of "KiNtu" languages in the 1980s. However, the latter term was quickly dismissed by many linguists since the word kintu exists in some places with the meaning "thing" which has no relation to the concept of "language". Some delegates at the African Languages Association of Southern Africa conference in 1984 reported that there are places where the term 'Kintu' has a derogatory significance. In such places, kintu refers to "thing" and is used as a dehumanizing term for people who have lost their dignity as human beings. Moreover, in some other places, Kintu is a mythological figure. The term "Kintu" remained apparently in occasional use in the 1990s in South Africa. In contemporary decolonial South African linguistics, the term "Ntu languages" tends to be used though the majority of linguists in Bantu speaking countries prefer “Bantu languages” by lack a better replacement term.
 Studies in African Linguistics: Supplement, Issues 3-4, Department of Linguistics and the African Studies Center, University of California, Los Angeles (1969), p. 7.