Thetical Grammar: An Introduction to Discourse Grammar based on Persian Examples

This article aims to introduce Discourse Grammar (DG) by using Persian examples. DS is comprised of Sentence grammar (SG) and Thetical grammar (TG) as two separate domains of investigation. On the basis of DG، the current paper focuses on those aspects of the language structures، namely theticals، which have been ignored or treated as marginal issues by previous models. It then presents how theticals play significant role in organizing discourse construction by being accompanied with sentence grammar. As a cognitive linking operation between theticals and sentence grammar، the phenomenon of Cooptation contributes immensely in the discourse organization. It will be also argued thetical elements behave differently at the syntactic، semantic and phonological levels in contrast to sentence elements in a discourse situation. In a sense، theticals are mainly triggered by the cognitive worlds of interluctors and operate at the pragmatic level of discourse organization. This means that such elements demonstrate a degree of elasticity and opacity، which make them quite different from the sentence structures which are rather fixed and transparent components of a discourse construction.