17.3 Constraining the Word Order

There are a bunch of new ideas which are mostly concerned with free word order and its consequences.

• Word order is left completely unspecified a priori and restricted only when needed. This can be achieved by representing word order orthogonally to constituent structure.

• The constituent structure of a sentence is modeled by a dependency structures, and its word order by an additional ordering relation (on the nodes of its dependency structure).

• The word ordering of a sentence is specified by word order constraints. The dependency structure of a sentence is expressed by role dependency constraints. Since both structure are interlocked, both kinds of constraints are also interlocked.

• Word order constraints can be encoded by finite set constraints in Oz and then be resolved by propagation and distribution.