Uniqueness of oblique arguments
The third of the well-formedness conditions in (31) (i.e. Uniqueness) states that “no Grammatical Relation may be assigned more than once by a single verb.” This statement seems to be contradicted by examples like those in (36), which have more than one oblique argument:
(36) a John carved a whistle [for his daughter] [with his pocket knife].
b Mary threw breadcrumbs [into the water] [for the fish].
c The farmer drew water [from the well] [with a wooden bucket].
There is a crucial difference between these examples, which are grammatical, and the ungrammatical example in Semantic roles and Grammatical Relations (21a): *John gave a bouquet of roses to his mother to Susan. That example is ungrammatical because it contains two oblique arguments of the same kind, namely two recipients. The grammatical sentences in (36), however, each contain two oblique arguments bearing distinct semantic roles.
These observations suggest that we can maintain the Uniqueness constraint, which seems to be needed in any case for the other GRs, by recognizing more than one oblique grammatical relation. The GRs of the various oblique arguments in (36) can be differentiated by reference to their semantic roles: OBLINSTR for instrument phrases; OBLBEN for beneficiary phrases; OBL GOAL for goal phrases, etc. These various OBL relations are said to be SEMANTICALLY RESTRICTED, since each relation can only be associated with a particular semantic role.1
In English, the difference between the various Oblique GRs is signaled in the syntax by the choice of preposition: with for OBLINST; for for OBLBEN; from for OBLSOURCE; (in) to for OBLGOAL; by for OBLAGT, etc. In some other languages, these GRs may be indicated by the use of specific case markers.
1. In some languages, a single clause can contain more than one secondary object. In such languages several different secondary object relations can be identified, which are again semantically restricted.
