The subject is the sentence constituent to which the predicate is assigned. Only noun phrases can act as subjects in Persian.

The following points are notable in the usage of subjects in Persian:

1. The subject is usually positioned ahead of the predicate:

   حکومتِ ایران با آمریکا قطعِ رابطه کرد.

   دو درویش در گلیمی گنجند.

   Owing to metrical conformation, the subject is also placed after the predicate:

   چار کس را داد مردی یک درم

   آن یکی گفت: «این به انگوری دهم!»

   Rumi (13^th Century AD)

   چنین گفت رستم به اسفندیار

   که: «کردار ماند زِ ما یادگار»

   Ferdowsi (10^th and 11^th Century AD)

   ببرد از من قرار و طاقت و هوش

   بتی سنگین‌دلی سیمین‌بناگوش

   Hafez (14^th Century AD)

2. As a basic principle, concord in the number, person and polarity is valid between the predicate and its subject (see 15•۱•a. for the cases of discord).

   In Persian, these grammatical categories of the predicate are non-ambiguously distinguishable in most instances (due to the syntactically distinctive conjugation).
   This fact fulfills the qualifications to apply Persian as a pro-drop language. This is the term for languages in which the subject can be deleted if it is a personal pronoun:

   (من) به دعا آمده‌ام، هم (من) به دعا باز روم

   که وفا با تو قرین باد و خدا یاورِ ما!

   Hafez (14^th Century AD)

   (تو) باز آی! که تا به خود نیازم بینی

   بیداریِ شب‌هایِ درازم بینی

   Rumi (13^th Century AD)

   (او) دوش می‌آمد و (او) رخساره بر افروخته بود

   تا (او) کجا باز دلِ غم‌زده‌ای سوخته بود

   Hafez (14^th Century AD)

In Indo-European languages one can find in the following cases sentences in which the agent does not appear as the subject:

• Natural and atmospheric events:
  • German: Es regnet sehr stark.
  • English: It rains very strongly.
  • German: Es dämmert in einer Stunde.
  • English: It dawns in an hour.
• Physical and spiritual feelings:
  • German: Es ist mir kalt.
  • German: Es gruselt mich.
• Shortcomings:
  • German: Es mangelt an Nahrung.

Such sentences are called impersonal sentences.

These examples clarify the following points:

1. Predicates of impersonal sentences are always in the 3^rd person singular.
2. The subject does not refer to the agent. It appears as personal pronoun in the 3^rd person singular. Such a personal pronoun is called expletive pronoun.
3. Application areas of impersonal sentences vary between Indo-European languages. For example, they are called “weather sentences” in English because they refer only to weather appearances.

Expletive pronouns are not needed in Persian as a pro-drop language: impersonal sentences have no subject. Impersonal sentences are applied in this language to express physical and spiritual feelings:

As the examples above show, the feeling person (the respective object) also appears as a (enclitical) possessive pronoun.

The impersonal sentences have to be differentiated from other forms which are also used in the 3^rd person singular and with an enclitical possessive pronoun: