One of the merits of the target article is to bring into sharp focus some of the fundamental issues that a syntax-based approach raises about knowledge of language and knowledge of the primitive elements in the various linguistic interfaces. Questions about roots, then, amount to questions on what a syntax-based model of grammar like DM has to say about lexical knowledge. The comments that follow centre on two such issues: the relations between the lists into which DM distributes lexical knowledge, and the nature of roots as morphological objects.