In Persian, nouns are not pluralized when the quantity is precise. For example, we say “three book” instead of “three books” because the cardinal number “three” indicates the quantity precisely.
| یک شب ⟨yek šab⟩ one night |
دو شب ⟨do šab⟩ two nights |
| هزار و یک شب ⟨hezâr o yek šab⟩ one thousand and one nights |
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| دو برادر دارم ⟨do barâdar dâram⟩ I have two brothers |
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| سه برگ کاغذ ⟨se barg kâǧaz⟩ three sheets of paper (“barg” is a classifier here) |
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Quantifiers are words that express quantity. The quantifier چند (“čand”, a few) indicates a quantity between 3 to 9. Therefore, it requires singular form.
| چند کتاب ⟨čand ketâb⟩ a few books |
| برای چند شب؟ ⟨barâ-ye čand šab?⟩ For how many nights? |
Quantifiers such as همه (“hame”, all) do not indicate the quantity precisely. Therefore, they require plural form.
| همهی کتابها ⟨hame-ye ketâbhâ⟩ All books |
| همهی بچهها ⟨hame-ye baččehâ⟩ All children |