Abstract:In North Sámi, verbs that form transitivity alternation pairs are always distinguished morphologically. However, even if morphology is seen as a reflex of the syntax, the syntactic structure underlying transitive and intransitive verbs in North Sámi cannot be directly read off from the morphology. Since the verbalisers have vocalic phonological realisations with some roots but consonantal realisations with others, and since consonantal realisations give the verb an additional syllable, one can get the impression that in some transitivity alternation pairs the transitive verb is derived from the intransitive verb, whereas in other pairs it is the other way round, and that in still other pairs both verbs are derived from a common base. On closer inspection it nevertheless appears that while in some cases the transitive verb is actually formed from the intransitive verb by causativisation, in other cases the transitive verb differs from its intransitive counterpart only in involving a Voice head. In addition, the language has a type of intransitive verb that are marked anticausatives, meaning that they have an expletive Voice head. The main difference between these verbs and the corresponding transitive verbs is the properties of Voice.