Dummettian anti-realism repudiates the realist's notion of ‘verification-transcendent’ truth. Perhaps the most crucial element in the Dummettian attack on realist truth is the critique of so-called “realist semantics”, which assigns verification-transcendent truth-conditions as the meanings of (some) sentences. The Dummettian critique charges that realist semantics cannot serve as an adequate theory of meaning for a natural language, and that, consequently, the realist conception of truth must be rejected as well. In arguing for this, Dummett and his followers have appealed to a certain conception of linguistic knowledge. This paper examines closely the appeal to speakers' knowledge of linguistic meaning, its force and limitations.