- What is the function of verbal stems?
- How is a past stem formed?
- How is a present stem formed?
- Does Persian have irregular conjugations?
Persian verbs have two simple stems and one compound stem. The simple stems are past stem and present stem. Old Persian has several compound stems but modern Persian has only one compound stem called causative stem. Verbal stems are used in conjugating verbs, making participles and also, in word formation. For example, past stem is used to conjugate verbs in past simple tense and present stem is used to conjugate verbs in present simple tense.
The past stem of a verb is obtained by removing -an from its infinitive form.
In Old Persian, verbs have various stems that derive from the same root. For example, by adding -a to the root bar (to take), we get the present stem bara and by converting the root to its weak form i.e. bərə and adding -ta to it, we get the past stem bərəta. The relation between a root and its stems has been lost in the transition of Old Persian to Middle Persian and consequently, to New Persian. Therefore, there is no formula for obtaining the present stem of a verb from its infinitive form. Knowing about verb formation and classification of irregular verbs can help you in learning and memorizing present stems.
Each verb whether regular or irregular has one and only one present stem for all persons. Therefore, as opposed to languages like French and Spanish, Persian does not have irregular conjugations. The following table shows the conjugation of دیدن (didan: to see) in present tense. Its present stem بین (bin) is irregular but its conjugation is regular:
You see (informal)
There is a regular rule for obtaining the present stem of a verb but it is only useful for native speakers: consider the imperative form of the verb and drop the prefix ب (and the intermediary consonant ی, in case it exists).
The causative stem of a verb is obtained by adding -ân to its present stem. Not all verbs have a causative stem. It is formed only for verbs that can have a causative meaning.