1. IntroductionAmerica is one of the countries that speak English. Because of the special North American culture, developing history and the social environment, American English has formed its certain unique forms and the meaning. Then it turned into American English that has the special features of the United States.American English which sometimes also called United English or U.S English is the form of the English language that used widely in the United States .As the rapid development of American economy, and its steady position and strong power in the world, American English has become more and more widely used. As in 2005, more than two-thirds of English native speakers use various forms of American English.The philologists of the United States had divided the English of the United States into four major types: “America n creating”; “Old words given the new meaning”; “Words that eliminated by English”;“The phonetic foreign phrases and the languages that are not from the English immigrates”[1].Compared to the other languages, American English is much simple on word spelling, usage and grammar, and it is one of the reasons that American English is so popular in the world.The thesis analyzes the differences between American English and British English. With the main part, it deals with the development of American English, its peculiarities compared to that of British English, its causes and tendency.2. Analyses the DifferencesAs we English learners, when we learning English in our junior or senior school, we already came across some words that have different spellings, different pronunciations or different expressions, which can be represented by following contrasted words: spellings in "color" vs. "colour"; pronunciations in "sec-re-ta-ry" vs. "sec-re-try";expressions in "first floor" equals to "the ground floor". With the above words, the former represents American English, and the latter represents British English. They are not errors but just the differences between the two languages.To be consistent in the use of English, and more importantly, to be understood easily, there is a need for the nonnative speaker to know that which words have distinct meanings and pronunciations depending on whether they are used by a Briton or an American. This is necessary not only for the sake of communication, but also for avoiding embarrassment.Many differences exist between American English and British English we have already knew. However, there are still many differences that we are not familiar with. In this part, the author will analyze the differences in several categories like spelling, pronunciation, grammar, usage and so on.2.1 SpellingThere are many differences between British English and American English in terms of spelling. After analysis by some linguists, it is said that the American English has a different tendency in pronounce, according to economical and phonetic standards. American spelling tends to reflect pronunciation, and British spelling tends to reflect grammatical or historical implications as well. Letters that not needed are being kicked out, and words are spelled as how they sound. The following examples can explain this.With "our" in words of British English like colour, humour, flavour, etc. are changed to "or" in the equivalent words of American English, like color, humor, flavor, etc. With the pronounce letter "u" being kicked out. Words ending with "-re" in British English are changed to "- er" in American English. According to its pronunciation, like "centre" and "metre" in British English, but "center" and "meter" in American English.More examples are as follows: (with the former is American English and the latter is British English)[2]center centre; check (money) cheque; color colour; curb kerb; gray grey; honor honour; inquire enquire; jail gaol; jewelry jewellery; labor labour; organization organization.2.2 Pronunciation differencesThere are of course great regional differences in pronunciation within both countries. For instance, basket，the word “a”in after、class and basket pronounce [æ] in American English，but [ɑ:] in British English.(The following examples mentioned all come from Oxford Advanced Learner’s English –Chinese Dictionary)(1) There is [hw] that correspond with [w] in American English. such as which，white，when，why. In British English :[wit∫]，[wait]，[wen]，[wai]，but in American English : [hwit∫]，[hwait]，[hwen]，[hwai].(2)There is [r] behind the vowel in American English ，such as: far，poor. In British English: [fa:]，[pu]，but in American English: [far]，[pur]，[hir].(3)In British English [l] pronounces surd before the vowel, (clearl)，and pronounces mix(混音) behind the vowel (darkl)；However,in American English, no word pronounces [l]. For instance，like, filling, till，well.(4) When the phonetic symbol [t] appears between the two vowels and behind the accentuation or between the voiced consonant and the vowel, it will pronounce [d]. Such as city: [`sidi].2.3Vocabulary differencesThe average use of the total English vocabulary, the number of words which are used only in one or the other country is very small, but the problem for learners of English is that these words are among the mostcommon in the language. There are many words that are used almost exclusively by Americans, which are understood by most Britons, and vice versa. But there are others that can cause difficulty. For example, most Britons know that Americans call biscuits cookies and flats apartments, but not so many know what an alumnus or a fender is. Similarly, Americans know that what they call their yard is called a garden in Britain and that trucks are Lorries, but common British English words like pistols or off-license may mean nothing to them.2.3.1Same meaning, different wordsThe majority of the significance in glossary between American English and British English is identical, but there still exists some difference. For example, the same thing can be expressed by different words in both languages. The following examples are typical. American English: British English:bathroom，toilet, W.C./or loo; closet, cupboard;corn ,maize; drugstore, chemist's;gas/ gasoline , petrol; line , queue; oven , cooker; round-trip ticket , return ticket; suspenders , braces; truck , lorry;underpass , subway; undershirt , vest;vacation, holiday; etc. [4]2.3.2. Same words, different meaningThe identical word expresses the different meaning between British English and American English.For example:Word American English British Englishrubber condom Tool used to erasepencil markingsdate appointment daycupboarddresser A wardrobeassistant2.4 GrammarBritish English and American English grammar are the same in most sense; there are however some interesting variations. For example,there are differences in certain verb forms. In American English, thepast tense of fit is fit; in British English, it is fitted. Americanssay I've gotten to know her well; while British: I've got to know her well.Other differences involved the use of the present perfect in British English and simple past in American English include already, just andyet.British English:I've just had lunchI've already seen that filmHave you finished your homework yet?American English:I just had lunch OR I've just had lunchI've already seen that film OR I already saw that film.Have your finished your homework yet? OR Did you finish your homework yet?As another example, Americans are much more likely to be technically correct in the agreement of collective noun and verb form than Britons.So in standard American English it would be: The team is playing wellthis season whereas in British English, it is common and acceptableto say the team are playing well. Similar differences can be seen inthe use of words like government, committee etc.: The government is... (American English). The government are… (British English).2.5 UsageThere are countless other small and interesting differences between American English and British English, which come under the heading of usage. Take the useful expression used in American English through, means up to and including. e.g. The exhibition is showing March through June. The equivalent expression in British English is from March to June, but this is ambiguous. Does the exhibition close at the end of May or the end of June? To avoid any misunderstanding, it is necessary to say something like: The exhibition is showing from March to the end of June.As another example: for Americans, the number billion has 9 zeros (a thousand million); for most Britons it has 12 zeros (a million million). Zero itself is a more common word in American English than in British English, where naught is more widespread. Americans say the number 453 as four hundred fifty three, whereas in Britain it would be said four hundred and fifty three. Time expressing also is different, and may cause confusion like 4/12/1981(month first) in the USA and 12/4/1981 (day first) in the UK.2.6 The causes of the differencesAt first there were no distinctions between British English and American English known to us in the development of contemporary English. But later in the 20th century, America emerged to be a great power and began to participate the practice of the world affairs. During the World War II, America demonstrated a great strength in the leadership of the world in world various forums. And after the world war, America emerged to be one of the only two superpowers in the world. Thus and thus, the distinctive ways Americans spoken, wrote was being analyzed, studied or learned by the people of other countries, including even British. What are the causes that led to American English distinctive from British English? Or we may say exactly were there any changes in thenew environment that led to the formation of American English in the near or around 400 years after British colonist’s settlement i n the American land (which took place at the beginning of the 17th century)?2.6.1 Old words, new meaningThose who came to the new American environment had to use their own words to name or express the new things that are similar to the original thing.For example, the word "corn”. In British English, it meant and still means the main cereal food "wheat". But in America then, the main cereal food was not wheat but maize, so they call this maize "corn". At that time, they add a word "Indian" before the "corn", so called "Indian corn" to point to maize. But later, for convenient, people in America just call it "corn" instead of using its full name "Indian corn”. So now we say "pop-corn" rather than "pop-Indian-corn". Americans speak "corn" to refer to wheat, while British still speak "corn" to refer to wheat. Of course, many other examples can also support this point.2.6.2 Native Language to Express Something New.These can be found in some names of places, of animals etc… Name of place: like Ohio (which originally means Ohio River), Mississippi (originally refers to Mississippi River which means Father of waters),Kentucky (means and of tomorrow)[5]Name of animals: like moose, raccoon, skunk etc.Name of plants: hickory, sequoia, squash etc.2.6.3 Brought in the Words of Other Languages.America is known as a country of different peoples, one word"melting-pot" can express this [6]. Even at the beginning of the 17th century when America became a colony of Britain, the people who settled in that land were not purely English or British. In fact, the total population of people from other countries of Europe or other part of world is far more than that of British. But all accept English that could understand as their language. But anyhow, inevitably, these populations other than British brought some words of their own languages in coexisted with the English.Later, as America developed, more and more people from other countries like China began to immigrate to America to find some new life. One sentence can express that urge " all people are eagle to see the Status of Liberty". In this, some words of their own languages were also brought into American English. Following more examples: From American Indian: moose(驼鹿)，chipmunk(金花鼠)，raccoon(獾熊)，sachem(酋长).From German: beer soup(啤酒汤)，semester(学期)，hex（符咒）.From French: cent(分)，voyager(航海家)，chute(瀑布).From Spanish: marijuana(大麻)， buckaroo（牛仔）， conch（海螺），poncho（披风）.This is also one of the main reasons that caused the formation of American English. Another example,Chop-suey,[7](a kind of American－Chinese food made by several sources like pork, rice, onion and so on) , word originally from the Guang Dong Hua language in China is taken by the Webster Dictionary. Expressions like "long time no see"(好久不见) imitate the way of Chinese saying and is taken by NIC's Dictionary of American English Phrases Essential American Idioms.[8]3. The Peculiarities of American English.The above section has described the causes of differences between British English and American English. Now this section will tell about the peculiarities of American English.As compared to the British English, there are several obviousfeatures of American English. First, part of the American English is of still of old or have past. Second, American English develops rapidly. Third, American English are consistent, a singly, not various kinds of American English. The formation of American English is deeply connected to its social prevailing custom and the nation disposition.3.1 Part of the American English is still of Old or having Past.Both in pronunciation and in word-spelling, For example, in American English the words like "fast, path and half" are not the same as the British pronounce [a:] , which actually the same as that of the British in the 17th century or 18th century. But now , British has already changed its pronunciation in these words to [fa:st]，[pa:I]，[ha:f]Another example like the words "sick" and "ill". [9] Originally these two words have the same meaning, no special different, but later in British English, "ill" means some soft discomfort, while "sick" means some tough disease, same with the feeling of sickness and disgusting. But in American English, now "ill " is rarely in use, and "sick " can be used to mean all kinds of discomforts or diseases both the little discomforts and the tough disease, which is the same as its original meaning.Another example: I guess as I think, I suppose, I believe e.g.: I guess you are wrong.(我想你错了) It was used wildly in Britain in 17th, and now they seldom use this. But Americans had kept it down.In this sense, American English is more close to the old English in some ways.3.2 Quick DevelopmentAt the same time, American English developed very quickly, became so distinctive that can be divided from what we called "the standard English" (which refers to the British English).[10] So now we come to the second feature of the American English that is its quick development.Now, in words amount, words of American English is bigger than that of British English. In structure, it's more complicated than that of British English. And thus, American English is more prepared to absorb more words, to change its spellings and pronunciations and it did do so. So now American English is different from the British English in many ways: like spelling, reading, meaning, tone grammar etc. For example, in spoken tone, American spoken English has much less ups and downs, unlike that of the British English. So American spoken- English is much simpler in tone, and easier to be understood, while the British English tone has many ups and downs, nice in hearing but harder in understanding.3.3 Consistence and creatingThe third feature of American English is its consistence and creating. For one thing, it has much more local accents or dialects than any other languages. And its local dialect does not have much effect on its national consistence. In the whole American country, people speak the same American English with the same standard. Among all the bigger countries in the world, no one has the similar language consistence as in America. For another, Americans have created new words and gave the new concepts by changing its form. For example: Pizzazz(时髦派头的人)，bellhop(俱乐部男侍)，debunk(揭露真相),cahoots(共谋)，taikonaut (太空人).4. The History and Recent Development of American EnglishHundreds years ago, Americans spoke the same kind of language that the British spoke. When they put words on paper, they use the same vocabulary and spelling. It is true that American English and British English grew from the same roots, but gradually the language came to be somewhat different.4.1 Origin of the divisionHistorical Linguists say that spoken English was almost the same in the American colonies and Britain two-hundred years ago. Americans began to change the sound of their speech after the Revolutionary War in 1776[11]. They wanted to make it different to separate themselves from the British in language, and then American English was no longer a colonial variety of the English of London but had entered its national period. Political independence was soon followed by cultural independence, of which a notable Founding Father was Noah Webster [12]. As a schoolmaster, Webster recognized that the new nation needed a sense of linguistic identity. Accordingly he set out to provide dictionaries and textbooks for recording and teaching American English with American models. The need Webster sought to fill was twofold: to help Americans realize they should no longer look to England for a standard of usage and to foster a reasonable degree of uniformity in American English. To those ends, Webster's dictionary, reader, grammar, and blue-backed speller were major forces for institutionalizing what he called Federal English.4.2 Noah Webster.Webster recognized that the new nation needed a sense of linguistic identity. Accordingly, he set out to provide dictionaries and textbooks for recording and teaching American English with American models. The need Webster sought to fill was twofold: to help Americans realize they should no longer look to England for a standard of usage and to foster a reasonable degree of uniformity in American English. To those ends, Webster's dictionary published in 1828.Webster's dictionary established rules for speaking and spelling the words used in American English. [13]Webster wrote that all words should be said in the order of the letters that spell them. For example, “c-e-n-t-e-r,” instead of theBritish “c-e-n-t-r-e.”Noah Webster said every part of a word should be spoken. That is why Americans say “sec-re-ta-ry” instead of “sec-re’try,” and many other examples.4.3 The ImmigrationThe different languages of many people who came to the United States also helped make American and British English different. Many of their foreign words and expressions became part of English as Americans speak it. The first wave of English-speaking immigrants was settled in the North America in the 17th century, and then more and more settlers realized that they had to talk in new ways to communicate with their new neighbors. Moreover, the settlers had come from various districts and social groups of England, so there was a homogenizing effect: those in a given colony came to talk more like one another and less like any particular community in England. All these influences combined to make American English a distinct variety of the language.4.4 DevelopmentAmerican English has developed in the change of the history and produced a great influence to the British English.4.4.1 Up-to-Now Development and Its TendencyIn 20th Century, especially after the two world wars, because of American surprisingly rapid development, and while at the same time, an Imperialist Britain has its great influence in the 20th century become a history, American English as a different part of English then formed. Based on America's powerful politics, economy, culture, etc, American style of culture and living began to overwhelm the rest of the world, (Britain, with no exception) through its films, media and other things. An influential linguist Sir Ernest Gowers has confessthat in his famous English dictionary A Dictionary of Modern English Usage, using the words "symptoms of surrender by the older competitor to the younger and more vigorous".[14]In the past fifty years, the United States has overtaken England as the primary disseminator of the English language.American Culture has influenced so many countries over the world. Food Corporations like McDonalds, KFC and Red Rooster are now found everywhere also American television programs like OC, Desperate housewives and Lost. American English is playing a big part in the world, and is affecting other languages in the world. This is also the same with American Music and films, which are constantly being promoted everywhere.The influence of America has taken the American English to the whole world. As Otto Friedrich et al said: “It was the British Empire, on which the sun never set, that originally spread English around the globe, along with tea breaks, cuffed trousers and the stiff upper lip. But when the imperial sun finally set after World War II, the American language followed American power into the vacuum.”[15]4.4.2 The Interfusion of both American and British EnglishSome linguists worried that the division between American English and British English would widen as time goes. But that's not true, as the increasingly developing of international media and communication; the gap between the two divisions of English has already tended to be minimized. Like the "fall", "OK" (All Right) in American English now used commonly in Britain. And the "lift" "sweets" in British English now also used by Americans often [16].So as time goes to a more modern future, the division between the two although still exists, but would be understood almost wholly by two different language users. And the two languages are affecting each other.5. ConclusionsThere are many differences between American English and British English, which explain why there exist American English and British English. And indeed, American English has its own distinctive features, which have already been described in detail in this thesis. All this differences and distinctive features of American English make it a special different branch of English.In author’s opinion,American English is full of human, plentiful ness ideas and unique. Since 20 century, with the affection of the movies, broadcasting and comic strips of the America, the speed of the broadcasting of the new words and phrases in England is as fast as in America. The British youth generation can speak American English very fluency. One magazine [17]in England even announced a series of articles exclusively, introducing the explanation of the meaning of the American slang, and the meaning of new phrase to educate the youth.So there is no doubt that American English had made the great contribution to the English development. In other words, they are affecting and developing each other.As English learners, when learning American English, and came across some words that have different spellings, different pronunciations or different expressions, we should be aware of using them. It is author’s sincere hope that this paper will serve for people to get more information about America English.Bibliography[1] Peter Trudgill & Jean Hannah. International English [M].北京：外语教学与研究出版社，2000:13-27[2] 陆国强. 现代英语词汇[M]. 上海：上海外语教育出版社，2000:44-70[3] 李嘉玉陈永培. 英语语调[M]. 商务印书馆，1989:86-96[4] 候维瑞. 英国英语与美国英语[M]. 上海：上海外语教育出版社，1992:120-135[5] 桂灿昆. 美国英语应用语音学[M]. 上海：上海外语教育出版社，1985:88-95[6] Lakoff.R. Language and Context [M]. 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