The Semantics of Yoruba Presupposition Triggers

There is a dearth of works on formal semantics study of African languages. Therefore, this paper investigates the semantic relation of presupposition in the light of relevant data from Yoruba language. It does not only identify Yoruba presupposition triggers but also investigates the extent to which they exhibit their triggering properties. The study shows that the negation of the set of propositions having the additive presupposition trigger, naa, cannot entail such propositions but their corresponding negations. It also shows that the interpretation of certain factive verbs in the language may result in presupposition failure in contexts where the experiencer referent in the main clause is not co-referential with the subject of the embedded complementizer (pe-)clause. It equally shows that the presupposition triggered by the preverbal item si 'still, again'may be entailed or non-entailed; and survives under negation by entailing the negated form of the concerned proposition.