English dominates culture, business and diplomacy. It also rules communication and science. The United Nations has adopted English as one of its six official languages. A2 English Test may be the world lingua, but its use is varied, both in written and spoken form.
English is divided into two distinct types, British English and American English. Oxford English Standard English or any other variation is a mere adaptation of these two kinds (especially when used for reference or consistency, such as in publications or media).
British English or UK English is a term Americans use when referring to English varieties used in the UK as well as outside of America. It is used as a way to separate the UK's written English and the rest of the world. Commonwealth English is a more accurate term, and it's widely recognized. British English as it is taught in UK schools has slight accents on some words. However, this formal language form, which we call British English, remains consistent.
Americans have also used British English as a term to describe spoken English versions in England. Meanwhile, British citizens claim that only they can speak "real English" and everyone else has a different or nonstandard accent. For example, in the UK there is no shortage of dialects or variants. There are many dialects in England. There are different dialects in each area. Most of the differences can be seen in Wales and Scotland.
American English (or US English), is the predominant form of English spoken today around the world. It's marked by "archaisms" (words which had changed meaning in England but continued to be used in the colonies), and new vocabulary, borrowed from French or Spanish colonists. In part, its widespread acceptance and wide distribution are due to USA’s products, including books, films, and songs.
American English as well as its regional variations have been intensified and have continued to exist in the USA. These variants are the result of elements from the native language of immigrants. This is especially true in terms pronunciation and vernacular terminology.
English is a second language for many countries including South Africa. British English dominates the teaching of English at schools in India and Australia. It is also used in Singapore, South Africa, Hong Kong and South Africa.
There are many varieties of English used in other countries. No one of these variations is "correct" or incorrect, except if it is aimed towards a particular audience.
In summary, the differences between written American English and British English in publications such as newspapers, textbooks and magazines (for example, in spelling and grammar) are minor, with only a few noticeable variations in similar media. In contrast, the spoken versions of English vary, especially in pronunciation, idioms, vocabulary, etc. Since there is not an official standard of English (American or British), it's best to use one specific form for consistency, clarity, and quality. The choice of type, whether American or British English is subjective.