WH-operators multiple copy spell-out in modern Irish

Irish has different complementizers depending on whether a clause is formed by an A-bar dependency without movement, via movement, or via binding of a resumptive pronoun. Despite these distinctions, these A-bar complementizers share the same phonological content, with the only difference being the mutation they trigger on the following verb. This paper reanalyzes these data, proposing that the verb mutation reflects the true realization of the C0 head, while the segmental content represents the WH-operator in Spec-CP. This paper analyzes this example of Multiple Copy Spell-Out and explores its implications for the order of operations in Syntax and Morphology.