Interestingly, the same might be true with languages. Quechua (from the Andean Mountains) only has three vowels (a, i, u). I can't find a reference, but AFAIK

Interestingly, the same might be true with languages. Quechua (from the Andean Mountains) only has three vowels (a, i, u). I can't find a reference, but AFAIK the main hypothesis was that a 3-vowel system made it easier to communicate across longer distances (i.e. across a canyon or valley in the Andes).