Yayan

Yayan is a theorized ancient form of the Chinese language used as a standard dialect by intellectuals during the Zhou dynasty (c. 1046 – 256 BC).

History
Yayan was mentioned in the Analects, which says:

"The Master’s frequent themes of discourse were: the Odes, the History, and the maintenance of the Rules of Propriety. On all these he frequently discoursed."

While the phrase has been agreed to refer to each of the Classic of Poetry, Book of Documents, and Book of Rites, scholars do not agree on the intended meaning of. Zheng Xuan (127–200 AD) interpreted it as: "The Master said: 'Elegant speech, proper speech it is'. Zheng said: 'When reading the laws and regulations of the ancient kings, it is necessary to pronounce their words properly; only then can righteousness be complete. Therefore, there should be no taboos. In the context of rituals, they are not recited, which is why we speak of adhering to them."

Some scholars have interpreted this "proper speech" phrase as possibly referring to a standard form of the language used by the literati of the era.

If historical, Yayan would have been based on the dialects of Old Chinese spoken around the Eastern Zhou (771–256 BC) capital of Luoyang.