A Corpus-Based Study of Obligatory and Optional Complements in Persian Based on Langacker’s Cognitive Grammar

IntroductionThe dependents of verb are among the most debated subjects on which a considerable body of research has been done. Yet, researchers have constantly had diverse opinions about their real identities. Complement, as one of the dependents of verb, is in the same boat. Some scholars have differentiated obligatory complements from optional ones, while others consider complements as obligatory elements and do not recognize an optional category. This article, based on Langacker’s (1987, 2013) Cognitive Grammar and through a corpus-based method, seeks to find out whether the Persian corpus verifies the existence of optional complements and if not, in what category can we place what is normally called optional complement. In other words, this research is to seek the answers to the following questions: Are there any optional complements besides obligatory ones based on Persian corpus-based data as well as Langacker’s Cognitive Grammar? If complements are merely obligatory, how can one categorize those elements called optional complements?MethodologyTo answer the above-mentioned questions, four dependents (subject, object, source and goal) of four salient motion verbs (raftan 'go', āmadan 'come', āvardan 'bring' and bordan 'take') in Persian were chosen to be studied. To this end, 300 tokens of each salient motion verb along with their dependents and the related linguistic context were randomly selected from the corpus of Hamshahri 2 to observe their corporal behavior.DiscussionLangacker (1987, 2013) distinguishes 3 dependents for heads including verbs, which are “complements”, “modifiers” and “adjuncts”. He defines complements as “a component structure that elaborates a salient substructure of the head. The head is thus dependent, and the complement is autonomous” (Langacker, 2013: 203). Conversely a modifier is “a component structure that contains a salient substructure elaborated by the head. In this case the head is autonomous, and the modifier is dependent” (Langacker, 2013: 203). And finally “a component structure which fails to either elaborate the head or be elaborated by it is called an adjunct” (Langacker, 2013: 205).Regarding the four dependents of the salient motion verbs under study, subjects and objects are complements since they elaborate the salient substructures of the verbs. Subjects elaborate the schematic trajectors of the verbs and objects elaborate the schematic landmarks of them. So the verb is, to a great extent, dependent on the subject and the object to complete its meaning. Such high conceptual dependence of the verb brings about its syntactic dependence too and as a result complements are obligatory and must constantly accompany the verb. The corporal behavior of the complements (subjects and objects) verifies this fact; from 300 tokens of each verb in Persian, there was not even a single sample in which the subject or the object was absent. Goals and sources, which tend to be considered as optional complements in the canonical viewpoints in Persian grammar, are, taking Langacker’s Cognitive Grammar into consideration,  modifiers since the motion verb elaborates their schematic trajectors which is a schematic process denoting a motional action. As a result, they are conceptually dependent on the motion verbs, hence being modifiers.3. ConclusionThe corporal behavior of subjects, objects, goals and sources as the dependents of the four salient motion verbs under study produces the following

Complements are solely obligatory elements since they elaborate the schematic trajectors or landmarks of motion verbs; thus, motion verbs are so conceptually dependent on the complements that they can never appear without them and as a result they become syntactically dependent on the complements as well. Sources and goals, on the other hand, are modifiers that are dependent on motion verbs to elaborate their schematic trajectors. Therefore, the relation that exists between the complement and the verb does exist between the modifier and the verb too but in a reverse direction. Although sources and goals are both modifiers considering Langacker’s Cognitive Grammar, the result of the study shows that there is a goal over source preference. The frequency of the goals is much higher than that of the sources and the result of the Chi-square test indicates that there is a significant difference between the presence of these two elements with salient motion verbs (P<0.05). This result aligns with Stefanowitsch and Rohde (2004), Kabata (2013) and Verkerk (2014). Although there is an asymmetrical distribution between sources and goals, neither of them are optional elements. Their behavior in the text corpus shows that the presence of these modifiers are determined by the context, i.e. if the context needs them, they have to appear and if not, they are not employed by it. For that reason, sources and goals are contextually obligatory and can be called “contextual supplements”.Studying adjuncts in the corpus shows that they are not optional either. These elements, too, have to be present if the context necessitates their being but if they are not summoned by the context, they are absent. So, adjuncts on the par with the modifiers are contextually obligatory and termed “contextual supplements” in this study. Based on the results of the analysis of the Persian text corpus, it seems that Langacker’s triple division of the dependents (i.e. complements, modifiers and adjuncts) does not meet the corporal behavior of these dependents.