Difference Between American And British English?

Some of the examples are:

Some American English words are shorter and easier than the original English.

If you don't know which one to use, it is better to follow the English scheme applied in your country.
My country uses the British English.

There are differences in accent, grammar and words. British accent needs no explanation if you've ever heard it. It is SO different from American.

The main grammatical difference is Perfect Tenses.

The Americans would say I just had a breakfast and Did you ever go to Spain. The British would stick to I've just had a breakfast and Have you ever been to Spain. There are some minor differences in preposition use and structure of sentences as well, but are really not important.

There are lists of words used differently in USA and UK. Some are just spelt differently, others have different meaning (rubber would be understood as an eraser in USA but as condom in UK).

By the way, the double negation is ungrammatical in English, but not necessarily in other languages. In my native Slovenian, we don't just use the double negation but even the triple and more. (Nihce nikoli nicesar ne ve -- English word by word translation would be: Nobody never not knows nothing.

Here are a few jokes to understand both the types of english better:

An American lady on the side of the road is very concerned when the nice Englishman calls out from under her car, "I can't quite see where the petrol is leaking out. Would you hand me a torch? 

Torch means a lighted flame in US english

2) An English exchange student asks someone “do you have a rubber?". Taken aback she says, “but I don’t even know you”. A bit confused, he assures her, “I’ll only be a minute. I’ll bring it right back”. 

Rubber means condom in US english

1. Use of present perfect tense and simple past tense

Speakers of American English generally use the present perfect tense (have/has + past participle) far less than speakers of British English. In spoken American English it is very common to use the simple past tense as an alternative in situations where the present perfect would usually have been used in British English. The two situations where this is especially likely are:

(i) In sentences which talk about an action in the past that has an effect in the present:

American English British/American English

Jenny feels ill. She ate too much. Jenny feels ill. She's eaten too much. 

I can't find my keys. Did you see them anywhere? I can't find my keys. Have you 
seen them anywhere?

(ii) In sentences which contain the words already, just or yet:

American English British/American English

A: Are they going to the show tonight? 
B: No. They already saw it. A: Are they going to the show tonight? 
B: No. They've already seen it. 

A: Is Samantha here? 
B: No, she just left. A: Is Samantha here? 
B: No, she's just left. 

A: Can I borrow your book? 
B: No, I didn't read it yet. A: Can I borrow your book? 
B: No, I haven't read it yet. 

2. Verb agreement with collective nouns

In British English collective nouns, (i.e. nouns referring to particular groups of people or things), (e.g. staff , government, class, team) can be followed by a singular or plural verb depending on whether the group is thought of as one idea, or as many individuals , e.g.:

My team is winning. 
The other team are all sitting down. 

In American English collective nouns are always followed by a singular verb, so an American would usually say:

Which team is losing? 

whereas in British English both plural and singular forms of the verb are possible, as in:

Which team is/are losing? 

3. Use of delexical verbs have and take

In British English, the verb have frequently functions as what is technically referred to as a delexical verb, i.e. it is used in contexts where it has very little meaning in itself but occurs with an object noun which describes an action, e.g.:

I'd like to have a bath. 
Have is frequently used in this way with nouns referring to common activities such as washing or resting, e.g.:
She's having a little nap. 
I'll just have a quick shower before we go out. 

In American English, the verb take, rather than have, is used in these contexts, e.g.:

Joe's taking a shower. 
I'd like to take a bath. 
Let's take a short vacation. 
Why don't you take a rest now?

4. Use of auxiliaries and modals

In British English, the auxiliary do is often used as a substitute for a verb when replying to a question, e.g.:

A: Are you coming with us? 
B: I might do. 

In American English, do is not used in this way, e.g.:

A: Are you coming with us? 
B: I might. 

In British English needn't is often used instead of don't need to, e.g.:

They needn't come to school today. 
They don't need to come to school today. 

In American English needn't is very unusual and the usual form is don't need to, i.e.:

They don't need to come to school today. 

In British English, shall is sometimes used as an alternative to will to talk about the future, e.g.:

I shall/will be there later. 

In American English, shall is unusual and will is normally used.
In British English shall I/we is often used to ask for advice or an opinion, e.g.:

Shall we ask him to come with us? 

In American English should is often used instead of shall, i.e.:

Should we ask him to come with us?

4. Use of prepositions

In British English, at is used with many time expressions, e.g.:

at Christmas/five 'o' clock 
at the weekend

Will they still be there on the weekend? She'll be coming home on weekends.

She studied chemistry at university.

She studied French in high school.

This place is different from/to anything I've seen before.

This place is different from/than anything I've seen before.

I promised to write to her every day.

I promised to write her every day.

5. Past tense forms

Below is a table showing verbs which have different simple past and past participle forms in American and British English. Note that the irregular past forms burnt, dreamt and spoilt are possible in American English, but less common than the forms ending in -ed.

infinitive simple past (Br) simple past (Am) past participle (Br) past participle (Am) 
burn burned/burnt burned/burnt burned/burnt burned/burnt 
bust bust busted bust busted 
dive dived dove/dived dived dived 
dream dreamed/dreamt dreamed/dreamt dreamed/dreamt dreamed/dreamt 
get got got got gotten 
lean leaned/leant leaned leaned/leant leaned 
learn learned/learnt learned learned/learnt learned 
plead pleaded pleaded/pled pleaded pleaded/pled 
prove proved proved proved proved/proven 
saw sawed sawed sawn sawn/sawed 
smell smelled/smelt smelled smelled/smelt smelled 
spell spelled/spelt spelled spelled/spelt spelled 
spill spilled/spilt spilled spilled/spilt spilled 
spit spat spat/spit spat spat/spit 
spoil spoiled/spoilt spoiled/spoilt spoiled/spoilt spoiled/spoilt 
stink stank stank/stunk stunk stunk 
wake woke woke/waked woken woken 

Note that have got is possible in American English, but is used with the meaning 'have', gotten is the usual past participle of get, e.g.:

American English British English 
You've got two brothers. (= you have two brothers) You've got two brothers. 
You've gotten taller this year You've got taller this year