The existence of a split in agrammatic Broca's aphasics’ comprehension of semantically reversible sentences with canonical vs. non-canonical word order have been explored in deep in the last decades. In this paper we present and discuss a new approach to canonicity effects that derives the asymmetry in a principled way from the Relativized Minimality approach to locality in syntax. The approach takes both processing and representational considerations into account thus avoiding problems, such as variation and complexity, encountered in non-integrated accounts. New data from a series of tests on both comprehension and production with an agrammatic Broca's aphasic patient are presented and discussed in light of the new proposal. Reduction of these asymmetries to a special case of the more general theory of locality allows generalizations to be made, which might be extended over different populations.