عنوان مقاله [English]
Scientific studies and academic works about Persian Language and literature discipline, like other disciplines, are to be based on principles of applying scientific language. Some of these principles are as follow: the language has referential function, a sign in scientific language is unmotivated, arbitrary, and conventional, function of sign and text is conveying the purpose, sign has the least rate of polysemy, and the explicit structures of language is applied. Some times in academic books in Persian language and literature discipline, language application deviates from these principles. The aim of this research is studying the types of this deviation and the research is based on qualitative research method and theoretical sampling. Based on research findings, the types of this deviation in these books, in lexis and group and clause level, are as follow: applying extra regularity, applying some kinds of deviation (historical, sematic, and stylistic), applying literary simile, quoting from literary texts in order to make poetic function, applying implicit lexis, and value judgement.