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 perfective past tense and present stem is used to conjugate verbs in perfective present tense.

Past stem

The past stem of a verb is obtained by removing “-an” from its infinitive form.

Infinitive Past stem
رفتن
raftan
رفت
raft
گفتن
goftan
گفت
goft
آمدن
âmadan
آمد
âmad
خوردن
xordan
خورد
xord

Present stem

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 New Persian. Therefore, there is no general rule to obtain 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.

It should be noted that 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:

Singular Plural
1st می‌بینم
mibinam
I see
می‌بینیم
mibinim
We see
2nd می‌بینی
mibini
You see
می‌بینید
mibinid
You see
3rd می‌بیند
mibinad
He/She/It sees
می‌بینند
mibinand
They see

Indirect rule

There is a regular rule for obtaining the present stem of a verb but it is mainly useful for native speakers:

  1. Consider the imperative form of the verb for second-person singular
  2. Drop the prefix ب (it could be pronounced “be”, “bi” or “bo”)
  3. Drop the epenthetic consonant “-y-” (if it exists)
  4. If it ends with “-ow”, change it to “-av”

Examples:

Verb 2S Imperative Present Stem
نوشتن
neveštan
to write
بنویس
benevis
نویس
nevis
یافتن
yâftan
to find
بیاب
biyâb
یاب
yâb
آمدن
âmadan
to come
بیا
biyâ
آ
â
رفتن
raftan
to go
برو
berow
رو
rav

Causative stem

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.

Verb Present stem Causative stem Causative verb
پوشیدن
pušidan
to wear
پوش
puš
پوشان
pušân
پوشاندن
pušândan
to cause to wear
to wrap, to cover
جوشیدن
jušidan
to boil
جوش
juš
جوشان
jušân
جوشاندن
jušândan
to cause to boil
خندیدن
xandidan
to laugh
خند
xand
خندان
xandân
خنداندن
xandândan
to cause to laugh
خوردن
xordan
to eat
خور
xor
خوران
xorân
خوراندن
xorândan
to cause to eat
سوختن
suxtan
to burn
سوز
suz
سوزان
suzân
سوزاندن
suzândan
to cause to burn