Why was chinese writing referred to as the key to the creation of a distinctive chinese identity?

Within the Chinese culture there were a multitude of different ethnic groups that used Chinese writing as a way to identify themselves, so the Chinese writing was used to bring the different ethnic groups together. Not only did Chinese writing unite the people, it was the primary tool used to create civilization among the people, more so than with any other culture, with the growth of the civilazation vitally dependant on it.