Valency (linguistics) - Valency in Syntactic Theory

Valency in Syntactic Theory

Valence plays an important role in a number of the syntactic frameworks that have been developed in the last few decades. In Generalized Phrase Structure Grammar (GPSG), many of the phrase structure rules generate the class of verbs with a particular valence. For example, the following rule generates the class of transitive verbs:

VP → H NP

H stands for the head of the VP, that is the part which shares the same category as the VP, in this case, the verb. Some linguists objected that there would be one such rule for every valence pattern. Such a list would miss the fact that all such rules have certain properties in common. Work in Government and Binding (GB) takes the approach of generating all such structures with a single schema, called the X-bar schema:

X' → X, Y’’…

X and Y can stand for a number of different lexical categories, and each instance of the symbol ’ stands for a bar. So A’, for instance, would be a kind of AP (adjective phrase). Two bars, used here for the complements, is thought by some linguists to be a maximal projection of a lexical category. Such a schema is meant to be combined with specific lexical rules and the projection principle to distinguish the various patterns of specific verbs.

Head-Driven Phrase Structure Grammar (HPSG) introduces a handful of such schemata which aim to subsume all such valence related rules as well as other rules not related to valence. A network is developed for information related to specific lexical items. The network and one of the schemata aims to subsume the large number of specific rules defining the valence of particular lexical items.

Notice that the rule (VP → H NP ) and the schema (X’ → X, Y’’…) deal only with non-subject complements. This is because all of the above syntactic frameworks use a totally separate rule (or schema) to introduce the subject. This is a major difference between them and Tesnière's original understanding of valency, which included the subject, as mentioned above.

One of the most widely known versions of Construction Grammar (CxG) also treats the subject like other complements, but this may be because the emphasis is more on semantic roles and compatibility with work in cognitive science than on syntax.