Fan Leiying (8) made a clear classification of teachers’ discourse and gave a detailed description of each category。 According to the expression pattern, there are six kinds of teachers’ discourse: spoken language, written language, sign language, demonstration language (used with teaching aids), drawing language (with the help of design), and music language (with the help of singing)。 It is considered that the first two are used widely in the teaching, yet the last four, only perform an assistant role。 What is more, there is another pision widely acknowledged, which includes teachers’ discourse in language classrooms and teachers’ discourse in content classrooms, which are devoted to teaching science, mathematics geography, etc。 

The findings of the study suggest that many teachers have an inaccurate perception to their own classes。 They are advised to make self-observation, find their problems, which exist in their teaching while they are not aware, and get self-development。 And according to attitudes and responses of the students, teachers should make flexible use of stating, questioning and evaluating part of teachers’ discourse and place enough emphasis on their voices。 In foreign language teaching, teachers’ discourse plays more important role because it is the major source of comprehensible target language input students receive。 Therefore, making the teachers’ discourse in language classrooms as the research object, the significance of this thesis is clear and evident。

2。2 Introduction to Speech Act Theory

Many linguistic theories take their premises in some rather simple-minded assumptions about human language。 It is nothing but a combination of “sound and meaning” thus in most descriptive grammars, or that language can be defined as a set of correct sentences thus in most generative-transformational thinking。 The basic flaw in such thinking is that it does not pay attention to language as an activity。 The Oxford philosopher John L。 Austin proposed speech acts, and discusses it in the Harvard University in 1955, later he published under the title How to Do Things with Words。 The phenomenon to be discussed is very widespread and obvious。 Speech act theory attempts to explain how speakers use language to accomplish intended actions and how hearers infer intended meaning form what is said。 

Austin pointed out that, contrary to popular belief, there is often no clear distinction between the two。 He was one of the first modern scholars to recognize that “words” are in themselves actions and that these speech acts should be systematically studied (Austin 86)。

As Austin indicated, we need to understand the difference between the locution and the illocution when we analyze a speech act。 The locution, which expresses the semantic meaning, is the practical form of words when speakers use。 Different from locution, the illocution or illocution force means that when speakers use illocution, they are expressing the following emotions: ordering, promising, threatening or thanking。 Next is a classical example that aims to manifest the deference between the locution and illocution when Matt expresses his meaning “give me some cash” to Mary。 

LOCUTION: When Matt says the words “give me some cash”, it can be semantically understood that “hand over me some money”, in which “me” refers to Matt。 

ILLOCUTION: Matt performed this act to command Mary to give him some money。论文网

We need to distinguish between the illocution and the locution because different locutions can have the same illocution force。 At the same time, in the different contexts, a locution may have different illocution forces。 For instance, when someone speaks “it is cold here”, he perhaps is expressing an order to close the window or an offer to close the window。