Systemic functional linguistics and pragmatics are two different but complementary language theories. Linguists have explained many linguistic phenomena in English and Chinese that indirectly express another function in one form from different angles. Under the framework of systemic functional linguistics, linguists believe that this phenomenon belongs to the mood metaphor in grammatical metaphor, which is caused by the inconsistency between speech mood and speech function. Indirect speech act in speech act theory thinks that it is caused by the inconsistency between the literal force and the verbal force of the speaker. There are many similarities between the explanations of these two theories.

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Paper Keywords Speech Act Theory; Indirect speech act; Systemic functional linguistics; Mood metaphor

I. Introduction

People form and express their thoughts through the meaning of language, which is the conceptual function of language. Another important function of language is to use language for communicative purposes, that is, the interpersonal function of language. Indirect speech act in pragmatics is the result of inconsistency between language form and function. When the literal meaning of language is inconsistent with the meaning of discourse, the use of language is indirect. Within the framework of Halliday's Systemic Functional Linguistics, grammatical metaphor includes conceptual metaphor and interpersonal metaphor, among which interpersonal metaphor can be divided into modality metaphor and mood metaphor. The so-called mood metaphor means that the chosen mood does not express its usual meaning, but expresses another meaning. This is also due to the inconsistency between speech tone and speech function. This paper will solve the indirect speech act in speech act theory from the perspective of mood metaphor in grammatical metaphor and the similarity between speech act theory and grammatical metaphor.