I would like to know more about genesis of Chinese language, few questions.

[sangormam]

Just out of curiosity.
According to:
http://en.wikipedia.org/wiki/Tone_(linguistics)
and:
http://wals.info/feature/13A?tg_format=map&v1=cfff&v2=cf6f&v3=cd00

most of languages in the world have no tonal system, or simple.
Rest of them use complex tonal system, where tone literally have a strong importance, required for understanding.
Like mandarin.
So i would like to know exactly why?
How it happened? When?
For example 3000 (or in http://en.wikipedia.org/wiki/History_of_China#Xia_Dynasty_.28c._2100_.E2.80.93_c._1600_BC.29) years ago mandarin also was tonal language?
What happened that they decided to use tones and not for example more words to distinguish meaning?
What happened that they choose pictographs, ideograms instead of any other form?

 

[abdrifter]

Personally, I don't think you'll ever find anything solid on this subject; conjectures and unsubstantiated theories at best. One might also ask why non-tonal languages use tones for other purposes, like statement/question difference (Russian, Hebrew etc.) as opposed to using some auxiliary lexeme. I'm pretty sure no one actually "decided" to start using tones though. As for opting for pictographs, maybe they didn't know any better?