EUREǂA ! Click sounds in African languages may be relics of 'Biokic' — the possible proto-human language
I think it took marine humans a few million years to develop the first advanced language on Bioko . Then people came to mainland Africa, or directly to Eurasia, and easily developed new advanced languages in those places. If so, the marine humans on Bioko surely played around making sounds under water. An effective underwater sound is the click, used by dolphins in their communication.
There are several click sounds in modern African languages: | —a dental click, ! —an alveolar click, ǂ —a palatal click, ǁ —a lateral click, and ʘ —a bilabial click. Most human click sounds can only be made in air, but some oral clicks can be made under water.
Here is good information about African languages and the click sounds ʘ, ǀ, ǁ, ǃ, and ǂ AfricaFreak and TheIntrepidGuide.
Youtube examples of African click speech
Youtube example of dolphin click communication under water
I’d like to call this possible proto-language 'Biokic' (or maybe Biokicic just for fun). That word has a nice ring click to it.--