From the perspective of language relativity, this paper attempts to analyze the causes of regional varieties that are the colonial expansion of England and cultural differences.

The openness of English vocabulary can also be seen in its regional varieties There are different characteristics in Britain English, Canadian English and so on.

But during the course of its development, many regional varieties have come into being, which is inconvenient for the learners.

English,increasingly globalized,has engendered various new Englishes with distinctive local characteristics,namely regional varieties of English,along with its popularization worldwide,which has profound historical background.

The causes of the phenomenon may be the different visual angle of language,the diachronic changes and the regional varieties of English.

Australian English,a regional variety based on the Cockney English of the late 18th century,has developed its peculiar phonetic features over the years.

To describe the regional variability of the complementary relationship between the actual and potential evapotranspiration,a pressure-temperature(p-t)state space was defined.

There is a general tendency to hyper-correction in English teaching,so it is essential to expound the relativity of correct English from the following dimensions: varieties of English,regional variants of English,and language change.