How did Khoisan click sounds become part of some Southern Bantu languages?

The incorporation of click sounds into certain Southern Bantu languages is the result of long-term cultural and linguistic contact between Bantu-speaking populations and indigenous Khoisan groups.12

As Bantu speakers migrated into Southern Africa, they interacted with Khoisan peoples who used clicks as a fundamental part of their consonant systems. Over time, these distinctive sounds were borrowed and integrated into the phonology of several Bantu languages.1324

The extent of this integration varies by language:
* Nguni languages, such as Zulu and Xhosa, have incorporated three types of click sounds into their consonant systems.234
* Other Bantu languages, such as Gciriku and Yei in Botswana and Namibia, have adopted a more extensive four-click system.12

While these Bantu languages are now considered "click languages," they are only derivatively so, as the clicks were not part of their original linguistic heritage but were acquired through their historical proximity to Khoisan speakers.2