difference

1、The differences between formal English and informal English
There may be special meanings of "formal" and "informal" English with which I am not familiar.
Formal English would be "standard English", and would be of more importance in written communication. Standard English would be the use of vocabulary and grammar that is as free as possible from idiomatic, slang or otherwise specialized use that would not be universally accepted or understood by fluent speakers world-wide. Informal English would be the English that local communities use, with all the idiomatic, slangy and quirky richness that that implies.
I n everyday conversation we do not have to follow the rules of grammar as carefully as we would in a formal address or a business letter. If we adhere too closely to formal rules of grammar in an informal situation, we may come across as being stuffy and unnatural. It is like wearing a tuxedo or a formal gown to an ordinary business meeting. Formal English follows rules of grammar very strictly. Sentences tend to be longer and more complex. It tends to be used in professional and business situations. It is also better organized and thought out. Informal English on the other hand is generally used with friends and family. A number of grammar expressions have common forms which differ in their formal or informal use. These differences are noted both in written and spoken English. However, they are most notable in written English.
Contracted Forms
Formal - Don't use contracted forms, use the entire auxiliary verb: They have lived in New York for many years.
Informal - Use contracted forms: They've lived in New York for many years.
Relative Structures
Formal - Use relative structures: The woman thought that it was important to be on time. Informal - Drop certain relative structures: The woman thought it was important to be on time. The Use of 'Whom'
Formal - Use 'whom' as an object: Whom have they chosen for the position?
Informal - Use 'who' as an object: Who have they chosen for the position?
Auxiliary Verb Usage
Formal - Always use the full form of an auxiliary: Have you finished your work?
Informal - Sometimes the auxiliary verb is dropped in informal speech. Note: This is often grammatically incorrect, but is certainly common in everyday usage: Finished your work?
Word Choice
Formal - Many words tend to be used in more formal situations. For example, certain verbs tend to be used in formal situations, but have other synonyms (often phrasal verbs) that are used in informal situations. Also, it uses more vocabulary derived from French and Latin (bigger words) It uses more synonyms and doesn't repeat the same words as much. The police investigated the situation.
Informal synonym: We looked into the situation.
Passive structures
Formal - It uses more indirect language, making it less personal. The student was given a book. Informal synonym: We gave the student a book.
2、The differences between written English and spoken English
Spoken English is the English which is oral and which we use to communicate with others in real life situation .Written English is the language which is not oral and which is used to
communicate with others in a more or less a formal situation.
On one hand, different occasions of usage entitle spoken English and written English with different stylistics. Spoken English is informal because it is usually used in conversation and it aims at expressing thoughts and communicating feelings. Sometimes we even speak out without thinking. Therefore, spoken English is easy to understand because of its natural, simple and vulgar language. Compared with spoken English, written English is very formal in that it appears in writing and it is often used to illustrate reasons and state ideas. Accordingly, writing English is usually persuasive, strong and flowery.
On the other hand, spoken English and written English have different grammar and structure due to different requirement in usage. Spoken English requires a person to response nimbly and express fluently. It doesn’t emphasize much on grammar and structure. One is prone to speak with sentence fragment and make many mistakes in a strict sense. Its structure is loose and complex sentences are not required. Slang also makes an indispensable part in spoken English. So long as the main idea is expressed clearly, the intention is reached. Whereas, written English should not only have no grammar mistakes and also much attention should be paid to make the structure as rigid as possible, since the articles have to be attractive to the readers. What’s more, tenses should be reconsidered. Inverted sentences can be adopted to emphases one’s opinions. Rhetorical sentences can be used to make a deep impression on the readers. Various clauses can embody the author’s writing skills. As a consequence, writers should choose his sentences and diction warily, like a sculptor sculptures his art.
3、The differences between British English and American English
B ritish English is the form of English used in the United Kingdom. It includes all English dialects used in the United Kingdom. American English is the form of English used in the United States. It includes all English dialects used in the United States.
T he spoken forms of British English vary considerably, reflecting a long history of dialect development amid isolated populations. In the United Kingdom, dialects, word use and accents vary not only between England, Northern Ireland, Scotland and Wales, but also within them. Received Pronunciation refers to a way of pronouncing standard English that is actually used by about two percent of the UK population. It remains the accent upon which dictionary pronunciation guides are based, and for teaching English as a foreign language. It is referred to colloquially as "the Queen's English", "Oxford English" and "BBC English", although by no means all who live in Oxford speak with such an accent and the BBC does not require or use it exclusively.
British and American English are the reference norms for English as spoken, written, and taught in the rest of the world. For instance, other member nations of the Commonwealth where English is not spoken natively, such as India, which often closely follow British English forms, while many American English usages are followed in other countries which have been historically influenced by the United States, such as the Philippines. Although most dialects of English used in the former British Empire outside North America and Australia are, to various extents, based on British English, most of the countries concerned have developed their own unique dialects, particularly with respect to pronunciation, idioms and vocabulary. Chief among other English dialects are Canadian English (based on the English of United Empire Loyalists who left the 13 Colonies), and Australian English, which rank third and fourth in the number of native speakers.
How to distinguish the British English and American English for English speakers？
Firstly，about the phonetic symbols. The phonetic symbols are the foundation of learning English language. You know that there are three kinds of phonetic symbols - IPA，DJ and KK. And there are relations among them，so it is quite easy to distinguish. You can find that all of the phonetic symbols are the same in general，besides the pronunciation of a few of them. You must listen to the standard pronunciation of phonetic symbols a lot and get more and more practice to read loudly，correctly.
Secondly，about the words and phrases. These two are also important. You'd better sum up the different usages of words and phrases between British English and American English，and remember them as many as possible. Because these words and phrases are limited，it's pretty easy to remember and use. It is important to accumulate every day.
Thirdly，about the sentences. You know the sentences are the most important in communications. Some of the usages are totally different between British English and American English. In British English，people speak completely and accurately.
There is still a long way to go if we want to learn English well.。