National Varieties of English

There are many varieties of English but British and American English are the two most common varieties taught in courses of English as a second language.

Differences between British and American English

Given that English is spoken by so many people and in locations as distant from one another as Calcutta and Toronto, is it possible to speak of a definitive English or are there many English languages? Especially amongst English teachers there is an ongoing debate as to the relevance, and even existence, of a 'Standard English' and what role it should play in the classroom.

There are many varieties of English but British and American English are the two most common varieties taught in courses of English as a second language.
Although British English and American English differ in certain aspects, both are correct and both have the status of 'Standard English'. Correctness is context-dependent, meaning that if you type “grey” with your word processor with the language setting set to English (US) the word will be underlined in red, indicating that it is misspelled. If you switch the 'set language' setting to English (UK) the red squiggly line disappears. Although the computer recognizes both as correct it doesn't do so at the same time.

British and American English differ in the following ways:

The use of the present perfect

In British English the present perfect is used to describe an action that has occurred in the recent past and has an effect on the present moment.
For example:
You've worked all morning. It's time for you to take a break.

In American English the following use of the simple past is also possible:
You worked all morning. It's time for you to take a break.
The sentence above would be incorrect in British English.

Other differences between the use of the present perfect and simple past involve sentences with the words, just, already, and yet:

In British English

In American English

I've just had breakfast.	I just had breakfast or I've just had breakfast.
I've already read that book.	I already read that book or I've already read that book.
Have you spoken to her yet?	Did you speak to her yet? Or Have you spoken to her yet?

Possession

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

In British English

In American English

Haven't you got any children?	Don't you have any children?
I've got a car.	I have a car.
She hasn't got a stereo.	She doesn't have a stereo.
He's got a new motorcycle.	He has a new motorcycle.

While these sentences are 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.) form.

The Verb Get

The past participle of the verb get is gotten in American English instead of got in British English:

In British English

In American English

I've got tired of the long winters here.	I've gotten tired of the long winters here.
She's got better at playing the piano.	She's gotten better at playing the piano.

Collective Nouns

Singular verbs are used with singular collective nouns in American English, while the singular or plural form is used in British English:

In British English

In American English

The government is/are meeting today in Parliament.	The government is meeting today in Parliament.
The British team is/are going to win this year.	The British team is going to win this year.
The company has/have no choice but to file for bankruptcy.	The company has no choice but to file for bankruptcy.

Vocabulary

The greatest difference between British and American English is found in their respective vocabularies. Sometimes the same word can have a different meaning or entirely different words are used to express the same thing.

Same word - different meaning

British English

American English

Mean	not generous, tight fisted	angry, bad humored
Rubber	tool used to erase pencil markings	condom
Let	to allow, to rent	to allow
Mate	a friend	a spouse

Spelling

The following are a few examples of the general differences between British and American spellings:

1.	Words that end with –our in British English, end with –or in American English.
		For example: colour, color; humour, humor; flavour, flavor
2.	Words that end with –ise in British English, end with –ize in American English.
		For example: recognise, recognize; patronise, patronize; organise, organize
3.	Words ending in –gue in British English, end with–g in American English.
		For example: dialogue, dialog; analogue, analog; catalogue, catalog
4.	Words ending in –re in British English, end with –er in American English.
		For example: centre, center; theatre, theater; fibre, fiber