Choosing Rhetorical Structures to Plan Instructional Texts

This paper discusses a fundamental problem in natural language generation: how to organize the content of a text in a coherent and natural way. In this research, we set out to determine the semantic content and the rhetorical structure of texts and to develop heuristics to perform this process automatically within a text generation framework. The study was performed on a specific language and textual genre: French instructional texts. From a corpus analysis of these texts, we determined 9 senses typically communicated in instructional texts and 7 rhetorical relations used to present these senses. From this analysis, we then developed a set of presentation heuristics that determine how the senses to be communicated should be organized rhetorically in order to create a coherent and natural text. The heuristics are based on 5 types of constraints: conceptual, semantic, rhetorical, pragmatic and intentional constraints. In order to verify the heuristics, we developed the spin natural language generation system. spin performs all steps of text generation but focuses on the determination of the content and the rhetorical structure of the text. keywords: natural language generation, text planning, Rhetorical Structure Theory, instructional texts