The norms governing the relations between and among sentences are a central, perhaps the central, kind of normativity operative in contemporary human natural languages. The sentence types in a contemporary natural language share basic features with the tool types in a tool kit. The epistemic norm of warranted assertibility is to be identified with the norms of the practices for using the tool types that are the sentence types in a language, and those practical norms of warranted assertibility themselves should be normatively assessed in terms of the norms of truth and of good, truth-preserving, inference. The fact that language itself is a supremely important tool kit implies that it is possible and to be expected that any sophisticated linguistic tool kit will have metalinguistic means for communicating beliefs regarding the linguistic tool kinds themselves. Our linguistic tool kits should, when used according to prevailing group practices, communicate instrumentally significant truths regarding the environment.