
"Dashtan" is one of the most frequent verbs in Persian and not only used as a simple intransitive verb, but it is also used as verbal part of compound verbs. Further this verb is used as an auxiliary verb to underline the progressive aspect, particularly in spoken Persian.
It seems that there are different unusual grammatical and semantic behaviors of this verb which make it an exceptional verb and at the same time difficult for the learners to master. The complexity and different behavior of this verb can be a result of the process of grammaticalization.