The study aims at understanding aspects of children’s literacy process based on the analysis of traces of a child’s thought processes concerning the production of a written text. The aim is to highlight the presence of the subject in language, considering the opacity of reality and language. A written text of a 5 year-old child was selected from the database of our research group, due to its originality of construction. Theoretical and methodological guidelines make use of aspects of Bakhtin’s enunciation theory, of the history of writing and of the relation between oral and written language. The use of indicial knowledge is based on the method of knowledge whose strength is grounded in the observation of revealing details. The analysis of the child’s text shows how different representational systems coexist in her efforts to convey meaning by writing. Systems governed by distinct organizational principles are used with varying functions; the same function may sometimes present instabilities in its uses. Different signs are used considering the interlocutor and the social audience (Bakhtin, 1998). These findings support the view that learning to write involves knowing the alphabetical principle of language as well as the complex web of other knowledge bearing on the production of language having social value. It is important to understand learning of writing as a process presenting instabilities and stabilities, and children as persons who are capable of learning in complex ways.