The first written texts in Ancient China appeared during the Shang dynasty, over 3,000 years ago. The spoken language existed long before that, and it was far from uniform in whole China.
In fact, languages of remote cities, as well as the languages that ruling dynasties used through ages, were sometimes unintelligible to each other.
The language that is now recognized as the predecessor of modern standard Chinese appeared some 1,000 years ago.
In addition to oracle bones, researchers found various inscriptions on different bronze artifacts.The inscriptions contained fragments of the Classic of Poetry, I Ching, and the Book of Documents.
Even though this writing system was not phonetic, each character was adapted to match a similar-sounding word.
The authors of rhyme tables such as the Yunjing used the Late Middle Chinese dialect, and they tried to interpret the former phonological system that was so much different from their own. So they performed a detailed analysis of the older language.
While the people spoke different varieties of middle Chinese, the written form of the old Chinese language was preserved thanks to influential classical works of literature that were written in Old Chinese.
Even though the language they spoke was different, newer authors tried to resemble the style of famous masters. The evolution of Chinese script continued as well, but the classical Chinese remained the only literary language.
The elites knew the classical form, read and wrote in it – yet no one spoke it anymore. With slight changes, classical Chinese was in use until the early XX century.
What is the language of the inscriptions found on oracle bones in ancient China?
It was the old Chinese.
How was middle Chinese divided?
It was divided into early and late middle Chinese.
What is the most valuable source of information about the phonetics of early middle Chinese?
Those were rhyme tables, and they were created in late middle Chinese.
What is the link and difference between the old and classical Chinese?
Classical Chinese was based on the language of literary masterpieces created in old Chinese.