DIFFERENCES BETWEEEN BRITISH ENGLISH AND AMERICAN ENGLISH

there are many "Englishes" -- variations of the language. In this article I’ll focus on the two mostly commonly used versions of English -- British and American English.
Before we take a look at some of the differences between the two main types of English I’d like to stress that these differences are somewhat minor and with the ongoing internationalization of our modern world they could even said to be diminishing.
The few differences that exist between British and American English tend rather to enrich communication than slow it down.

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:

I've lost my key. Can you help me look for it?
In American English the following is also possible:
I lost my key. Can you help me look for it?

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:

I've just had lunch
I've already seen that film
Have you finished your homework yet?

American English:

I just had lunch OR I've just had lunch
I've already seen that film OR I already saw that film.
Have your finished your homework yet? OR Did you finish your homework yet?

Possession

There are two forms to express possession in English. Have or Have got

Do you have a car?
Have you got a car?
He hasn't got any friends.
He doesn't have any friends.
She has a beautiful new home.
She's got a beautiful new home.

While both forms are correct (and accepted in both British and American English), have got (have you got, he hasn't got, etc.) is generally the preferred form in British English while most speakers of American English employ the have (do you have, he doesn't have etc.)

The Verb Get
The past participle of the verb get is gotten in American English. Example He's gotten much better at playing tennis. British English - He's got much better at playing tennis.

Vocabulary
Probably the major differences between British and American English lies in the choice of vocabulary. Some words mean different things in the two varieties for example:

Mean: (American English - angry, bad humored, British English - not generous, tight fisted)

Rubber: (American English - condom, British English - tool used to erase pencil markings)

There are many more examples (too many for me to list here). If there is a difference in usage, your dictionary will note the different meanings in its definition of the term. Many vocabulary items are also used in one form and not in the other. One of the best examples of this is the terminology used for automobiles.


American English - hood
British English - bonnet

American English - trunk
British English - boot

American English - truck
British English - lorry

Once again, your dictionary should list whether the term is used in British English or American English.

For a more complete list of the vocabulary differences between British and American English use this British vs. American English vocabulary tool.

Prepositions
There are also a few differences in preposition use including the following:

American English - on the weekend
British English - at the weekend

American English - on a team
British English - in a team

American English - please write me soon
British English - please write to me soon

Past Simple/Past Participles
The following verbs have two acceptable forms of the past simple/past participle in both American and British English, however, the irregular form is generally more common in British English (the first form of the two) and the regular form is more common to American English.

Burn
Burnt OR burned

Dream
dreamt OR dreamed

Lean
leant OR leaned

Learn
learnt OR learned

Smell
smelt OR smelled

Spell
spelt OR spelled

Spill
spilt OR spilled

Spoil
spoilt OR spoiled


Spelling
Here are some general differences between British and American spellings:

Words ending in -or (American) -our (British) color, colour, humor, humour, flavor, flavour etc.
Words ending in -ize (American) -ise (British) recognize, recognise, patronize, patronise etc.

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