Project A2 investigates the role of implicit linguistic and world knowledge within common ground, focusing on the differing at-issue potential of selectional restrictions (markers of linguistic knowledge) and common factual or stereotypical knowledge (markers of world knowledge). A2 hypothesizes that examining these distinctions through the lens of CG is crucial to resolving the long-standing challenge of clearly delineating them. Our experiments will address semantic conflicts and conceptual conflicts. By analyzing how these conflicts interact with various CG management devices, we aim to deepen our understanding of CG’s cognitive architecture.