Hi Jackie. I included some links that go into detail on this subject. What fasinates me is, who, or what group of people decided that a certain group of sounds would mean something?? example: you grunt something to imply meaning to an object or idea, and I grunt another to denote the same thing, who decides who's grunt will be the standard?? Deep questions. . .
I'll be sure the share any further information that I find on this matter.