Apparent filler–gap mismatches in Welsh

<jats:title>Abstract</jats:title><jats:p>Filler–gap dependencies involving a clause-initial filler constituent of some kind followed by a matching gap are an important feature of human languages. There are also certain cases where what looks like a filler differs in some way from the following gap. In the case of Welsh there is a mismatch between apparent filler and gap in some nominal cleft sentences. It can be argued, however, that the initial constituent is not a filler but one term of a hidden identity predication. There are various other complexities in this area. There is one word, the identity copula, which only allows a complement that is a gap. There are two cases where a deletion process conceals the identity of the initial constituent in a cleft sentence, making a Progressive Phrase look like a Verb Phrase and a Predicative Phrase look like an Adjective Phrase or a Noun Phrase. Finally, there are three cases where a verb with a gap as a dependent has a special form, two cases involving the predicational copula and one involving all transitive verbs. Thus, a number of mechanisms are required to deal with the full set of facts.</jats:p>