  However, while it is certainly legitimate to propose a special  relationship between speakers and grammars, unanswered questions  remain about the precise nature of cognizance. Is it a  representational relation, like belief? If not, what does  ‘learning a grammar’ amount to? If so, are speakers'  representations of grammar ‘explicit’ or  ‘implicit’ or ‘tacit’ — and what,  exactly, do any of these terms mean? (See the papers collected in  MacDonald 1995, for discussion of this last issue; see Devitt 2006  for arguments that there is no good reason to suppose that speakers  use any representations of grammatical rules in their production and  comprehension of language.) Relatedly, how does a speaker's  cognizance of grammar (her ‘competence,’ in Chomskyan  parlance) function in her linguistic ‘performance’  — i.e., in the actual production or comprehension of an  utterance?