Verb formation

Historically, there are certain suffixes for making new verbs: -idan, -ândan/-ânidan, -estan

Suffix -idan

Suffix -idan is used for making a verb from a noun, present stem, …

Suffix -ân(i)dan

Suffix -ân(i)dan is used for making a causative verb. It forms by first adding -ân and then the verb-maker suffix idan. In modern usage, the i in ânidan usually drops:

Suffix -estan

Suffix -estan is similar to -idan but is mainly used in middle Persian:

Present stem

The present stem of such verbs is obtained by removing the verb-maker suffix. Therefore, these verbs can be regarded as regular verbs:

verbpresent stem
tarsidantars
tarsân(i)dantarsân
tavânestantavân

NOTE Not all verbs ending in -idan are constructed verbs. There are a few verbs that end in -idan but since they are not constructed verbs, their present stem is irregular. Examples:

verbpresent stem
didanbin
shenidanshenav