Ok. I see how you mean in general about evolving from one creature to another through mutations and all that stuff but going from an animal like language to a spoken language just seems a bit strange how it can happen. Like going from animal noises to perfectly formed sentences of spoken language seems hard to grasp.
It's because you don't and is reasonably separate from evolution.
The language evolves and is past down through the generations. each generation adds to the language and thus gets more detailed and complex.
