If the claim is that the majority of humans speak a language which includes huh? as a feature, then sure. But that doesn't seem very interesting scientifically...

By calling it a universal word, I guess I thought they were referring to the concept of linguistic universals [1], which are interesting since they might suggest something about the deeper way in which our brains work. To make a claim about linguistic universals like that I really think they should study more than 10 (31) languages.

According to this page [2], 44% of people speak an Indo-European language, and 96% speak a member of one of the top 10 language families. The remaining 4% includes 84 language families. I imagine there's a ton of variety there, and for understanding human language and cognition they all probably have just as much value as the larger language families.

[1] https://en.wikipedia.org/wiki/Linguistic_universal

[2] https://www.vistawide.com/languages/language_families_statis...

Universal should mean that virtually every human in history used it. Just because something is pervasive in modern societies does not mean is a fundamental feature of human nature. Language is universal. Fear and anger are universal.

Yes, Xhosa isn't "all clicks", as you point out, I've a friend who can speak a little of it, but just my guess about a "click language" people might have half-heard of and assumed was all clicks.

I've been trying to recall where I heard a "pure clicking" language, I've a feeling it was a bushmen docu from Botswana - and it might just be that the hunters used words that only required clicks, or I misheard, etc..

Anyway, http://listverse.com/2018/08/10/10-extraordinary-languages-t... and https://www.britannica.com/topic/click-languages mention Damin, which sounds (no pun intended!) like it might have been mainly composed of clicking sounds?

Perhaps what I heard was slang/dialect tailored to the activity, which IIRC was hunting.