While there are certainly many more varieties of English,American and British English are the two varieties that are taught in most ESL/EFL programs.Generally,it is agreed that no one version is "correct" however,there are certainly preferences in use.The most important rule of thumb 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 (i.e.The color of the orange is also its flavour - color is American spelling and flavour is British),this is of course not always easy - or possible.
There are also differences in the English spoken by different socio-economic groups in any particular region.Received Pronunciation (RP),which is "the educated spoken English of south-east England",has traditionally been regarded as "proper English"; this is also referred to as BBC English or the Queen's English.The BBC and other broadcasters now intentionally use a mix of presenters with a variety of British accents and dialects,and the concept of "proper English" is now far less prevalent.[