While there are certainly many more varieties of English, American and British English are the two varieties that are taught in most English Foreign Language (EFL) lessons. Generally, it is agreed that no one version is "correct" however, there are certainly preferences in use.

Here are just a couple of differences between the two main varieties of English:

Consistency of Spelling

The most important rule is to try to be consistent in your usage. If you decide that you want to use American English spellings then be consistent in your spelling. For example:

The color of the orange is also its flavour.

Color is American spelling and flavour is British. Here are the sentences with consistent British and American spellings:

The colour of the orange is also its flavour. The color of the orange is also its flavor.

Use of the Present Perfect

In British English the present perfect is used to express an action that has occurred in the recent past that has an effect on the present moment. For example:

In American English the following is also possible:

In British English the above would be considered incorrect. However, both forms are generally accepted in standard American English. Other differences involving the use of the present perfect in British English and simple past in American English include already, just and yet.

British English:

American English: