In Persian, letters are written from right to left and digits from left to right. Persian writing system is technically called “abjad”. It is different from a typical alphabet in that, only consonant sounds have a dedicated letter. Vowel sounds are either denoted with diacritical marks or represented by certain consonants. Therefore, Persian writing can be called a consonantal alphabet. Short vowels are denoted with diacritics and long vowels are represented with consonants. For example:
- We write پدر ⟨pdr⟩ and read it as “pedar” (father). The short vowels “e” and “a” are absent in writing. When needed, they can be denoted with diacritics: پِدَر (see vowel marking)
- We write دوست ⟨dvst⟩ and read it as “dûst” (friend). Here, the consonant “v” represents the long vowel “û”.
History of Abjad
Persian has been written in various abjad scripts since 2300 years ago. Arabic writing system is also an abjad and originates from kindred scripts. It was not an unfamiliar writing system to Iranians and in fact, Iranians (“Ibn Muqla” and “Ibn al-Bawwab” among other figures) played the major role in the standardization and development of Arabic script. Iranians also added letters for the consonant sounds that were not found in Arabic. This extended version is called Perso-Arabic script and has been used for writing Ottoman Turkish, Kurdish, Urdu and several other languages.

Benefits of Abjad
Persian has been spoken for thousands of years. It has countless dialects and diverse vowel patterns. Limiting our discussion to New Persian, an abjad writing system has allowed it to be written in a consistent form for more than 1100 years. Vowels are normally absent in writing. Readers infer or supply them according to the target dialect, era or style. For example:
- پرسیدن ⟨prsydn⟩ is pronounced “porsidan” in the standard dialect of Iran and “pursidan”, in the standard dialect of Afghanistan as well as many regional dialects inside Iran. In either case, the written form is identical. Persian speakers pronounce it with short “o” or short “u” depending on their dialect.
- کردن ⟨krdn⟩ is pronounced “kardan” in the three standard dialects of Persian but in some regional dialects including that of Kerman, Yazd and Shiraz, it is pronounced “kerdan”. There are also dialects, where it is pronounced “kordan”. In any case, the written form is identically کردن.
- رسیدن ⟨rsydn⟩ is normally pronounced “residan” in Iranian Persian but in literary speech, it is pronounced “rasidan”, which is its classical pronunciation. In either case, the written form is the same.
During Sasanian era (224–651 CE), Iranians devised Avestan alphabet in order to record Zoroastrian scripture precisely. Avestan alphabet consists of 37 consonants and 16 vowels and is one of the most complete alphabets to this day. Our ancestors could use it for writing Persian as well but they knew that an abjad is more suited to a language that is spoken in a vast empire and has various dialects. Avestan was a dead language by then and needed to be recorded accurately but Persian was an alive language with a different set of requirements to meet. The versatility of Persian writing system has allowed it to be written almost uniformly across regions and generations. Persian speakers would not encounter considerable difficulty in reading historic texts and manuscripts. Dialects typically differ in vowels rather than in consonants. With vowels out, the language can be written in a uniform orthography.
