When and how was the recognition acquired that the human being is an existent endowed not only with external behavior but also with an inner world? How has Chinese literature represented the invisible inner world not yet expressed in words? Modern Western novels invented the art of melding a character's inner thoughts with the narrative voice by adopting the free indirect style. On what linguistic forms, then, have Chinese novels relied to report the characters' thoughts? In this article, we examine these questions in the context of issues that have arisen since the linguistic turn. That is to say, how did the Chinese language invent the "inner world"? And how was the "inner world" constructed in a Chinese context? In traditional vernacular stories, a character's inner world is often grasped in contrast to his or her external behavior. However, the narrator depicts both the inner and outer movements of the character from an omniscient point of view as if they are equally visible objects. In this regard, the rendering of a character's thoughts in the traditional vernacular story differs entirely from the invisible and mysterious inner world in a modern sense. In Wu 呉 dialect novels of the late Qing 淸,such as Haishang hua liezhuan 海上花列傳 (Lives of Shanghai Flowers; 1892-93), jiuwei gui九尾亀 (Nine-Tailed Tortoise; 1906-10), and jiuwei九尾狐l (Nine-Tailed Fox; 1908-10), the characters speak in the Wu dialect, but interestingly the same people think to themselves in Mandarin. This phenomenon can be linguistically interpreted as follows. Whereas their utterances are given in direct speech, thereby introducing the Wu dialect into the dialogue, their thoughts are quoted in indirect speech, which inevitably results in stylistic adjustments in Mandarin by the narrator. This linguistic fact would suggest that the assumption that interior thought is more essential than one's external voice does not apply to traditional Chinese narratives. However, the direct quotation of inner thoughts appears in the final stage of the traditional novel in the early twentieth century, in Wu Jianren's 呉趼人vernacular novel Henhai恨海 (The Sea of Regret; 1906) and in the literary novel Yuli hun 玉梨魂 written by Xu Zhenya 徐枕亞 in 1914. Significant use of the free direct/indirect style enables the character's inner emotions to be revealed to readers without any mediation on the part of the narrator. It was the stylistic innovations of these early twentieth-century novels that invented the human "inner world" in Chinese literature, and this led to the establishment of the modern vernacular style in the Literary Revolution, as well as the prolific achievements of the May Fourth novels.