American and British English are both variants of World English. As such, they are more similar than different, especially with "educated" or "scientific" English. Most divergence can be ascribed to differing national histories and cultural development and the way in which the two national variants have changed correspondingly.
It was said by Sir George Bernard Shaw that "England and America are two countries separated by the same language".
Written forms of American and British English as found in newspapers and textbooks vary little in their essential features, with only occasional noticeable differences in comparable media.
This kind of formal English, particularly written English, is often called 'standard English'. It is therefore important for teachers to be aware of the major differences between the two. And while lexical differences are the easiest ones to notice, knowledge of grammatical and phonological differences can be useful not only for teachers to be aware of, but also to be able to deal with in business world. Lack of awareness can lead to embarrassment and confusion.
Another thing which has become apparent is the fact that there are no definitive answers. Not only do different counties / states use different terminology but there appears to be differences between generations as well. All this makes it very difficult to produce information with which everyone agrees.
What has become very evident over the years is just how much language is merging between all the various countries. In the UK we have adopted many, many "Americanisms" into everyday language and, I believe, some British terms are now used in the USA. This is probably due to travel and the wide exchange of TV programmes etc.
Some people asked, "Which is better American or British English?" Generally, it is agreed that no one version is "correct" however, there are certainly preferences in use. It depends upon which English you will be most exposed to. If you are moving to the US then learn American English, if you're going to work for a British company then learn British English. And do not forget there are many different kinds of English and the rising star of International English.
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 (ie 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. That both British English and American English are accepted on the examinations as long as you consistently use either one or the other. In other words, do not mix!
Some of the key differences between these two languages; however, most of the words are exactly the same. Firstly, one can easily notice that the accents are much different. Some words are slightly different. For example, in American English the undergarments of a person are called "underwear." However, in British English, it is simply called "pants." Thus, some words can be easily confused in the opposite cultures.
There are also some reasonably consistent spelling differences. There are some common rules for American English. In the following examples listed below, the first is UK English and the second is American English.
• Where UK, Australian and NZ English often use the letter group of our, in American English the u is omitted.
favourite / favorite
neighbour / neighbor
colour / color
• UK English uses an s where American English often substitutes a z.
capitalisation / capitalization
recognise / recognize
• In word building, UK English doubles the final consonant where it is preceded by a vowel, whereas American English does not. For example:
traveller / traveler
labelled / labeled
• Some words which are spelt with a 'c' in the noun form but an 's' in the verb form of some words are not spelt with the 'c' in American English – both noun and verb forms retain the 's'.
practice / practise
licence / license
• Some words ending in 're' in UK and Australian English are spelt with 'er' in American English.
centre / center
kilometre / kilometer
• UK English retains the old style of retaining 'oe' and 'ae' in the middle of some words, whilst American English uses just an 'e'.
encyclopaedia / encyclopedia
manoeuvre / maneuvre
• Some words in UK English retain the 'gue' at the end, as opposed to just the 'g' in American English.
dialogue / dialog
catalogue / catalog
The best way to make sure that you are being consistent in your spelling is to use the spell check on your word processor (if you are using the computer of course) and choose which variety of English you would like. As you can see, there are really very few differences between standard British English and standard American English. However, the largest difference is probably that of the choice of vocabulary and pronunciation.