f speech and political speech before analyzing Obama's speech at Town Hall Meeting in Shanghai Science and Technology Museum.
There are different classifications of speeches according to different criteria. According to the field with which the speech if concerned, public speech can be classified into political speech, academic speech, military speech, and so on. Obama's speech belongs to political speech. According to their general purposes, speeches fall into three categories: informative speech, entertaining speech and persuasive speech. Political speech including presidential speech is under the category of persuasive speech, which aims to persuade audience to agree and perhaps to act. According to the formality of speeches, they could be divided into formal speeches and informal speeches. Obama's speech belongs to the formal speech because it is delivered on formal occasions. As far as channel is concerned, there are impromptu speeches, extemporaneous speeches, and speeches written to be spoken. Obama's speech is prepared before hand.
Political speech is an important social-cultural phenomenon of the West. It is one that the speaker, usually on behalf of a certain class, society, or party, makes to the audience on some important matters and relationships at home and board. The primary aim for every political speech is to form the highest expressions of the aspirations of the groups for whom the speaker speaks. However, the aim of political speeches is not single but multiple most of the time. Besides the intention of expressing certain thoughts and communicating ideas, there can be very complex intentions to influence the public opinion and obtain some political purpose. In Obama's speech, he delivers his speech with the aim of building a good relationship with China, propagating western political ideas for freedom, equity and democracy, and getting the economic order for goods from China.
Before Barack Obama, many other American presidents have made speeches in China. For example, Ronald Reagan's speech in Fudan University in 1984,William J. Clinton's speech in Peking University in 1998,Geoge W. Bush's speech in Tsinghua University in 2002. On one hand, they are all belonging to the part of presidential formal state visits to China. They are all political speeches delivered at similar occasion; hence they are many similarities in usage of polite language. On the other hand, they took place in different times and they were made by different persons, so differences may be found among their speeches. Because they are guests of Chinese, all of their speeches are more or less full of politeness' language, while Obama's speech is the most single-hearted. This shows that the comprehensive national power between China and America is getting narrower.
2. Leech's Politeness Theory
As for the research of politeness' language, scholars home and abroad raise relatively many theory modes and search methods from the perspectives of rhetoric, psychology, sociolinguistics and pragmatics. Politeness as a main research subject of much concern has been and is still enjoying much popularity with people specialized in the area of pragmatics.
In 1967, American philosopher Grice proposed the cooperative principle and later collected into his essays, Lo