The Grammaticalization of vastǝn in Gilaki

Modal verbs are a group of helping verbs that represent modal concepts in relation to the main verb and are the result of the occurrence of grammaticalization, the process by which the grammatical items are created. In this study we investigate the grammaticalization of modal verb vastǝn (have to) in Gilaki, one of the Iranian languages of the western branch. Gilaki is a language with poor historical data, so we use Hopper's principles of gammaticalization (1991) as the main framework of the research to identify cases of grammaticalization. We also use the concepts word order, reanalysis, analogy and desemanticization. We measure the effectiveness of these principles and in some cases we present an alternative analysis. In this paper after introducing the theoretical framework, we analyze the data. The results show that with regard to borrowing of modal element of obligation from Persian to Gilaki, two functional items including modal element of tendency and negation element are specific for Gilaki. Changing in the imperative mood system is the most important result that is obtained through grammaticalization of modal verb vastǝn which makes Gilaki different from other Iranian languages.