constraints on WH-questions

[Holger Diessel]

Dear all,

I am looking for typological works on the formation of WH-questions.
Some 25 years ago Keenan and Comrie proposed the accessibility
hierarchy, which states important constraints on the formation of
relative clauses. Subsequent work by Hawkins and others has argued that
the accessibility hierarchy is motivated by the complexity of filler-gap
constructions. If so, it seems reasonable to assume that the formation
of WH-questions is constrained in a similar way as the formation of
relative clauses (in languages in which WH-questions involve
extraction). Is there any typological work that investigated possible
constraints on the formation of WH-questions in this regard?

Thanks in advance,

Holger Diessel