Where was the heartland of the pre-historic Chinese branch of languages (or that of the entire language family)?
This wiki page, History of China, provides some &quot;basic&quot; knowledge:
The &quot;earliest written record of Chinese&quot; (aka oracle script) was found in bones (of ox, cow) and shells (of tortoise) in 安陽. It's about 商 dynasty (1600–1046 b.c.).
About the preceding one, 夏 dynasty (bc 2070 - 1600), there was one newest discovery, related to the myth &quot;great flood&quot;, and 鯀 &amp; 禹.
This megaflood occurred in 1922 ±28 b.c., in the place of 喇家, in today  Qinghai.
A relevant article: Rocks tell story of China's great flood.
have fun :)