Local and Global Implicatures in Wh - Question

The unacceptability of wh-question disjunctions can be given a semantic explanation if we take the partition theory of questions as a basis (Groenendijk and Stokhof 1982, 1984). According to this theory, a question defines a partition of the logical space. A disjunction of two questions is then a union of two partitions, which is not again a partition: there are overlapping cells. Thus the disjunction of two questions is not a question. According to Krifka (2001), the reason for the deviance of wh-question disjunctions is also pragmatic, the underlying assumption being that speech acts cannot be coordinated disjunctively. Speech acts are operations that, when applied to a commitment state, deliver the commitments that characterize the resulting state. Speech act disjunction would lead to disjunctive sets of commitments, which are difficult to keep track of. According to Krifka (2001), a question like (2) could only be interpreted in the way