Charles Fillmore: Grammatical Cases

  Charles Fillmore was one of the first linguists to introduce a representation of linguistic knowledge that blurred this strong distinction between syntactic and semantic knowledge of a language. He introduced what was termed case structure grammar and this representation subsequently had considerable influence on psychologists as well as computational linguists.

      Linguistic knowledge is organized around verbs or more precisely, a verb sense. (A verb may have more than one sense or meaning and these are represented separately. For example, to run for office is a different sense of run than to run to first base, and these would be two different representations in a case grammar.)

     Associated with each verb sense is a set of cases. Some of the cases are obligatory and others are optional. A case is obligatory if the sentence would be ungrammatical if it were omitted. For example, John gave the book is ungrammatical.

     The cases associated with a verb seem to be associated with questions that we one would naturally ask about an event. Who did what to whom when? The representation seems well adapted to the retrieval of the information provided in a sentence. This feature was particularly appealing to psychologists and computational linguists

  A second interesting feature is that the same representation is provided to both the active and passive forms of the sentence. This feature would be consistent with a finding that we rarely recall the exact syntactic form of the sentence but do recall the basic information provided by the sentence.

     One of the consistent findings in human sentence understanding is that we seem to draw these inferences automatically. And, we rarely remember whether or not such information was explicitly stated in the sentence. This observation is consistent with some of the features of a frame-based representation as suggested by case structure grammar

     Another aspect of the case grammar representation is that it can be effectively used to parse incomplete or noisy sentences. For example, while John gave book is not grammatical, it is still possible to create an appropriate case grammar parse of this string of words. However, case grammar is not a particularly good representation for use in parsing sentences that involve complex syntactic constructions.