FLUVIAL • DICCIONARIO INGLES.COM • Definition of Fluvial

... the language, which is most closely allied to the Benga dialect, to be one of the great South African family, variously called Kafir, because first studied amongst these people; Ethiopic (very vague), and Nilotic because its great fluvial basin is the Zambezi, not the Nile. As might be expected amongst isolated races, the tongue, though clearly related to that of the Mpongwe and the Mpangwe, has many salient points of difference; for instance, the liquid "r" is wholly wanting. According to Mr. T. Leighton ...

— Two Trips to Gorilla Land and the Cataracts of the Congo Volume 1 • Richard F. Burton