Niger-Congo

The Niger-Congo language family dominates sub-Saharan Africa. It is one of the world's largest language families, encompassing over 1,500 languages spoken by approximately 450 million people across the region.

The Nile, Congo, Niger, and Zambezi river

Nile=Sudan

Congo=Congo Basin/Democratic Republic of the Congo

Niger=Guinea, Mali, Niger, And Nigeria

Zambezi=Zambia

There are several major groups of Sub-Saharan languages. The largest is the Niger-Congo group.

All language families are equally "important", but what is probably meant is: What is the name of the largest language family in South Africa, that is the language family having the most speakers who use it as their mother tongue? That would be the Nguni (comprising Zulu, Xhosa and Swazi languages).