In LIS, it is possible to find cases where a content interrogative contains two copies of the same wh-sign, as in the following example. The non-manual component can either occur with the wh-signs only, or optionally spread over the whole clause.
wh wh
what yesterday buy what
‘What did you buy yesterday?’
When doubling takes place, one wh-sign sits in sentence-initial position while the other one sits in the canonical sentence-final position. Sentences with doubling can be naturally used in certain contexts only if the question presupposes that there is someone or something that is the answer to this question. For example, the sentence above is natural if the signer is playing the role of a police officer who has arrested a suspect. During the interrogation, the suspect admits to have stolen something. In that context, the police officer can happily utter that sentence because it is given for granted that there is some object that has been stolen.
Another attested case of doubling takes place when qartichoke combines with another wh-sign. This happens in certain colloquial registers. As the following examples show, the wh-sign and the qartichoke preferably occur in sentence-final position with the order ‘wh-sign – qartichoke’.
wh
a. arrive who qartichoke
‘Who arrives/has arrived?’
wh
b. ix2 do what qartichoke
‘What are you doing/did you do?’