Yep, this is a really interesting question. I had a long discussion about this on another forum, and it turns out linguists really have no idea why clicks are r

Yep, this is a really interesting question. I had a long discussion about this on another forum, and it turns out linguists really have no idea why clicks are restricted to African languages. The best we could come up with was that click sounds are just too difficult to evolve — there’s no easy way for some random English sound (for instance) to turn into a click. On the other hand, if a neighbouring language has click sounds, that can start to provide almost a ‘pathway’ for clicks to come into the language.