Abstract: This paper investigates the syntactic and semantic commonalities and differences among direct discourse, indirect discourse, and free indirect discourse within the cartographic framework, arguing for the syntactic presence of a Discourse Layer in the left periphery of direct discourse and free indirect discourse clauses, and establishing the core status of the Speaker and the Subject of Consciousness within this layer. Building on this, the paper further compares the three reported speech types with respect to their root-clause properties and tense features, exploring the differential role of the Discourse Layer in the sentence-completeness mechanisms of tense-prominent versus tenseless languages. It concludes that the Discourse Layer either encodes the Speaker, representing communicativity, or encodes the Subject of Consciousness, representing subjectivity: the former drives tense-prominent languages to achieve completeness by anchoring speech time, while the latter drives tenseless languages to achieve completeness by checking subjective elements such as mood and modality.