 By ‘lexical syntax’ Cheney and Seyfarth mean a kind of semantic compositionality of characteristic vocalizations. If a vocalization (call) were to have lexical syntax, the semantic significance of the whole would depend on the relation of the structure of parts of the call to the structure of what they signify. The absence of ‘lexical syntax’ in call systems suggests that it is illegitimate to think of them as having anything like semantic structure at all.