Both proper names and common nouns, when used as terms of address in Romanesco, can be preceded by the particle a (a Nando! ‘Hey, Fernando!’) and undergo truncation of the poststress material ((a) dottó’! ‘Hey, doc!’). The article presents a panchronic study of this construction in Romanesco, showing how and when truncation and the vocative particle a first arose and providing a synchronic analysis of the conditions under which they occur today. Vocative truncation is widespread in Central-Southern Italo-Romance, where it obeys conditions that vary subtly across time and space and that the article will touch upon based on the studies available to date. These conditions will be described in detail for Romanesco, showing that they are hierarchically organized and involve all levels of linguistic analysis: the list includes (a) a part-of-speech condition, (b) a condition referring to the syntactic constituent, (c) a semantic/pragmatic condition, (d) one of prosodic minimality, and finally (e) one of lexical semantics, relative to the animacy/definiteness hierarchy. Also the occurrence of the a particle is subject to conditions which are syntactic-textual, pragmatic and phonological in nature and which identify preferences rather than clear-cut (un)grammaticality, contrary to those that constrain truncation.