Shattuck-Hufnagel (1986) (henceforth S-H), in discussing the significance of ‘slips of the tongue’ for a model of processing, is particularly concerned with attempting to establish to what extent some of the constructs posited by phonologists in their characterisations of phonological structure can be shown to have a role in the planning of speech production. On the basis of the ‘MIT corpus’ of errors (collected by Merrill Garrett and herself), particularly those involving vowels, she argues for a role in planning for aspects of syllable structure, placement of lexical stress, and distinctions and dimensions such as those commonly captured by feature notations. My concern here is with some further aspects of syllable structure: I shall suggest that her data provide support for even more detailed structural properties than are proposed by S-H herself; indeed, that one uncertainty in assessing the significance of the data can be resolved by an independently motivated analysis of subsyllabic structure. I shall not repeat here the details of the classification of errors on which S-H's discussion is based (1986: §1); what is significant in the present context is that errors of various types provide a motivation for particular subsyllabic units.