This chapter addresses how languages express negation and evidentials in statements, questions and commands. Negation is typically conveyed via negative affixes or negative particles, but it can also be expressed in other ways, including tonally or via changes in word order. Evidentials encode source of information morphologically or syntactically; the chapter discusses both direct evidentials, which indicate that evidence was gathered through the senses, and indirect evidentials, that signal information gathered indirectly. This chapter also provides conlanging practice, includes a set of guided questions to facilitate the incorporation of negation and evidentials in a conlang, and describes how negation and evidentials are expressed in the Salt language