Trask (1993: 221–2) defines pronouns as The lexical category, or a member of this category, whose members typically function as noun phrases in isolation, not normally requiring or permitting the presence of determiners or other adnominals, and whose members typically have little or no intrinsic meaning or reference’, and he divides them into personal, reflexive, demonstrative, indefinite, interrogative, and relative. In discussing pronouns it is also useful to refer to their role as anaphors, in that they may refer to, or ‘take their interpretations from, other items in the same sentence or discourse’ (ibid., p. 15): ‘John saw the book’ – ‘He saw it’, and as deictics, in that they may ‘make crucial reference to such factors as the time or place of speaking or the identity or location of the speaker, the addressee or other entities’ (ibid., p. 75): ‘this’, ‘that’ (in the context of pronouns). The vocative, insofar as it might be needed, is identical with the nominative.