A Study of Covariance between Language and Society

I INTRODUCTION
The development of human society is a process of differentiation and integration. The differentiation of the society always brings about the language differentiation; while the integration of the society requires the language integration at all time. As a famous linguist Chen Yuan goes： ＂Language is a variable, and society is another variable. These two variables are influencing each other; interacting each other; restricting each other and changing together. This is what we called CO- VARIANCE.＂ When the society is changing gradually or changing dramatically, language must be changing in pace of the society.