David Sapir (1971) proposed a classification of Atlantic into three branches, a northern group, a southern group, and the divergent Bijago language of the Bissagos Islands off the coast of Guinea-Bissau:[2] Sapir's classification is widely cited in handbooks on African linguistics (e.g. Bender 1989, Williamson & Blench 2000), and is also used in the Ethnologue (22nd ed., 2019).

The unity of the Atlantic languages—as traditionally defined—has long been questioned, e.g. Dalby (1965), who argued for the Mel languages as a primary branch of Niger–Congo.

At the current state of research, the wide concept of Atlantic (i.e. including the Southern languages) within the Niger–Congo family is no longer held up.

Furthermore, Merrill suggests that due to the divergence of the Atlantic languages, the homeland of Niger-Congo may lie in the northwest of sub-Saharan Africa.

[1] Merrill (2021) also notes that Tenda and Biafada-Pajade share similarities with each other, and may possibly form a linkage.