The distinction between phonological and syntactic words, most evident in cases of discord between the domain of the Dokean phonological word and constituent structure, is considered. The integrity of the unit noun class prefix + stem, a central concept in Bantu morphosyntax, is questioned. It is argued that the class prefix is sister not to a following noun but to the whole of the NP (noun prefix). Support for this claim derives from limitations on High Tone Spread, a tonological process sensitive to syntactic brackening within an object NP. The analysis, offered in the framework of autosegmental phonology, also provides an explanation for the so-called ‘neutral tone’ prefixes of Tsonga, previously described by reference to dissimilation.