Grammaticalization and (inter)subjectification in an Iranian modal verb: A paradox resolved by Dutch

This paper deals with the grammatical and semantic development of a modal verb in four West Iranian languages: gu/ga in Kahangi, gijabon in Semnani, boGostæn/bogostæn in the Takestan dialect of Tati and goan in Vafsi. Field work data demonstrate that, from the perspective of the grammaticalization and (inter)subjectification literature, this verb in these languages poses a challenge. It occurs as a non-grammaticalized full verb and as a grammaticalized auxiliary. Yet the full verb features an arguably more (inter)subjectivized meaning than the auxiliary: the former expresses volition, the latter dynamic, deontic and epistemic modal meanings. The absence of historical data for these languages does not allow the puzzle to be resolved directly, but a comparison with the modal verb hoeven ‘need’ in Dutch, which in the present-day language has properties similar to those of the Iranian verbs, and which has been investigated diachronically, suggests a solution: the present situation may be the result of a convoluted diachronic evolution, in which the semantic and grammatical developments do not align. The case thus demonstrates that one cannot easily draw conclusions from synchronic observations about diachronic relations between forms and/or meanings.