In the following, designs are conceived as proposals for innovations. As such, they occur in language. Their reality is unlike the reality that a design proposes. As communications, they need to inspire the stakeholders of designs, and enter networks of coordination in which they become realized to be used, consumed or serve as replacements of existing artifacts. Professional designers operate in language as well, in a specialized design discourse whose distinct terms, methods, and practices enable them to generate possible futures, evaluate their virtues, and participate in multi-disciplinary development teams. This chapter moves beyond the common conception of communication by exploring the properties of conversation on the one hand, and of discourse on the other hand, both in view of their roles in design practices. It also contrasts design discourse with other widely respected discourses.