Voice syncretism is widely attested crosslinguistically. In this paper, we discuss three different types of Voice syncretism, under which the same morpheme participates in different configurations. We provide an approach under which the same Voice head can convey different interpretations depending on the environment it appears in, thus building on the notion of allosemy. We show that, in all cases under investigation, allosemy is closely associated with the existence of idiosyncratic patterns. By contrast, we notice that allosemy and idiosyncrasy are (...) not present in analytic passive and causative constructions across different languages. We argue that the distinguishing feature between the two types of constructions is whether the passive and the causative interpretation comes from the Voice head, thus forming a single domain with the vP or whether passive and causative semantics are realized by distinct heads above the Voice layer, thus forming two distinct domains. (shrink)