In this paper we try to analyse the cases of insulting or defamation from the viewpoint of speech act theory. In general, lawyers judge the cases depending on whether the utterance include the expressions which can lower the reputation of hearers. But the methodology is considered to be subjective, so the judgement often remains in controversy. Instead we present an objective method which is based mainly on the speech act theory.
Following Tiersma (1987), we assume that language crimes such as insult or defamation consist of an illocutionary act and a perlocutionary act. The analysis proceeds as follows: Firstly we find out the expression reflecting the concept of ‘social face’, based on the work of Kim and Yang (2011). Secondly we check out the felicity conditions of the proposed illocutionary act ‘defaming’ which contains the concept ‘social face’ as its component. Lastly we examine if the utterance violates the ‘social face’ in the sense of impoliteness strategies in Culpeper (1996). We analyse some precedents by the proposed framework, which show that our linguistic analysis can complement the legal analysis which may contain some errors.