I often hear it said that China is the Roman Empire that never fell.

I believe what people mean by this is that there is a linguistic and cultural continuity for thousands of years in China which is unparalleled by any other civilization.

Is this really true though? Throughout its history China has splintered and rejoined into successor states, sometimes from within and sometimes from foreign rule such as the Mongol Yuan Dynasty and Manchu Qing Dynasty.

In terms of linguistic continuity, from what I understand China was extremely diverse (even just within the Sino-Tibetan group) until the last century when mass media culturally assimilated and homogenized much of the urban areas.

So is there any truth to the notion that China is a more continuous civilization compared to say the Western world, or does it just so happen that China is more politically united then the West in the last few centuries.