Thematic and Grammatical Hierarchies in Persian Language

There is no one-to-one correspondence between semantic roles and grammatical relations. Based on the concept of implicational hierarchy, some linguists have attempted to identify the relationship between grammatical relations and thematic roles. In this descriptive research, based on the Persian Proposition bank, Semantic Role Corpus in the Persian Language, and Persian Syntactic Dependency Treebank, the semantic hierarchy for different grammatical relations like subject, direct object, indirect object, subject complement and object complement have been explored in the one hand and also the grammatical hierarchy for different thematic roles like agent, experiencer, cause, theme, stimulus, attribute have been considered on the other hand. The syntactic and semantic corpora above consist of approximately 30,000 sentences and about half a million tokens. Observations showed that in the Persian language, among different kinds of semantic roles, the first candidate to be the subject is the agent followed by the theme, experiencer and cause. For the object position, the theme outranks the result which in turn outranks the topic and the recipient. In the direct object position, the most frequent role is the location followed by theme, recipient and destination; and finally, in the subject and object complement position, the attribute is the most frequent role among the other thematic roles in the sentences. On the grammatical hierarchy for thematic roles, subject outranks the object, as the agent and the experiencer; subject outranks the adjunct as the cause; triple preposition outranks the subject as the stimulus; object outranks the subject as the theme, and finally, the subject complement outranks the subject complement as the attribute. Apart from this dominant tendency, this research showed that there are other remarkable correlations between syntactic and semantic arguments; for example, the agent in addition to subject position can be placed in the direct object, indirect object, and even in the adjunct position. The appearance of experiencer in object position and stimulus in subject position is the other remarkable result.