The Iranian languages belong to the Aryan (Indo-Iranian) family of languages and are among the oldest languages that are a sub-family of the Indo-European languages. The Aryans came to be divided into two major groups in the 2nd Millennium BC. One group migrated to north-west India (Punjab and the surrounding areas) via the present-day Afghanistan and then permeated into other lands while the other group gradually entered the Iranian plateau and settled down in its various parts. Since then, the Aryan language branched into the Indian and Iranian languages, each following its own course. Like many other languages, the Iranian languages, too, have passed through the three – Old, Middle, and Modern – phases.
The Ancient Iranian Language
The split between the Indians and the Iranians resulted in the emergence of two ancient languages, viz. the ancient Indian language and the ancient Iranian language. Even though no trace of the actual ancient Iranian language – which was the common language of all the Iranian tribes – remains today, what did survive from it came to be known as the ancient Iranian languages that were widely spoken over an extensive region until the downfall of the Achaemenian Empire in 330 BC. From among the ancient Iranian languages, only two have survived in their written forms – the Old Persian and the Avestan– while not much remains from the other languages.
a. Old Persian: Old Persian was the language of the Persian tribe that had settled in the south-west of Iran (the present-day Fārs province) after entering the Iranian plateau and had established the great Achaemenian Empire following the downfall of the Medians in 550 BC. The scribes of the Achaemenian period used the Aramaic language and script for writing on hides and papyrus and used the Elamite and at times the Babylonian cuneiform language and script to inscribe on stone and clay. However, in all probability, they began inventing a special cuneiform script for Old Persian during the reign of Kurosh II (Cyrus II), popular as “Cyrus the Great”, which became widespread during the reign of Dāryush I (522-486 BC).
The cuneiform writing of Old Persian, which was exclusively used in the inscriptions of the Achaemenian kings, ran from the left to the right. This system which contained thirty-six alphabetical-inflectional characters, eight determinants, and two word dividers as well as some symbols to depict numbers is one of the simplest forms of cuneiform writing.
The surviving inscriptions of the times of the Achaemenian kings are sometimes in a single language (Old Persian), sometimes bilingual (Old Persian and Elamite), at times trilingual (Old Persian, Elamite, and Babylonian) and rarely in four languages (Old Persian, Elamite, Babylonian, and Ancient Egyptian hieroglyphics).
b. Avestan: The Avestan or Avestaic is the language of the Avestā, the holy book of the Zoroastrians. The oldest part of the Avestā, the Gāhān, are hymns attributed to Zardusht (Zoroaster), the prophet of Ancient Iran who according to some historians lived in Khwārazm in the first part of the 1st Millennium BC. The dialect used in the Gāhān, the Yasna Hafta as well four other sacred hymns of the Zoroastrians are referred to as the Gāhāni dialect. The other parts of the Avesta have been written in a newer dialect known as the “modern dialect”.
Traditionally, the Zoroastrians believe that the Avesta was written in gold on twelve thousand pieces of cow-hide during the reign of the Achaemenians and came to be destroyed after Alexander of Macedonia’s invasion of Iran and the eventual downfall of the Achaemenian Empire. They also believe that Avesta was first put into a written form during the reign of the Parthian king, Balāsh (probably Balāsh I, 51 t0 76-80 AD) and for a second time during the reign of Ardashir Bābakān(ruled 224-240 AD), the founder of the Sassanian dynasty. The recent researches, however, indicate that that until the Sassanian period, the Avesta had been transferred by word of mouth or oral communication from one generation to the next and in all probability a script was invented for writing it only during the reign of Shāpur II (309-379 AD) on the basis of the Middle Persian text script as well as the Zaburi Pahlavi script. The Avestan script that is also referred to as the “religious script” was written from left to right with the help of fifty-three alphabetical characters. In this script, each word was separated from the next one with the employment of a dot (Fig. 2).
c. Other Ancient Iranian Languages: From among the two other ancient languages, i.e. Median (native to the west and north-west) and the Ancient Sakan (native to both sides of the Caspian Sea, the plains of Southern Russia, and Transoxiania) only a few words that are mainly proper nouns have survived in the inscriptions of the Achaemenian kings and the texts of the Greek historians.
The other ancient Iranian languages of which no signs remain and regarding the existence of which verification can be found only through a study of linguistics were Ancient Parthian, Ancient Soghdian, Ancient Khwārazmian, and Ancient Bactrian.
Middle Iranian languages
a.The Western Branch :The Western Middle Iranian languages include Parthian (Parthian Pahlavi) and Middle Persian (Pahlavi or Sassanid Pahlavi).
I. Parthian: Parthian was the mother tongue of the Parthian tribe which originated from “Pahlah” or “Pahlao” (Parthia), that included the north of the present-day Khorāsān as well as parts of recent-day Turkmenistan. One of the leaders of this tribe called “Ashk” or “Arshak” overcame Antiochus II, the third Seleucid king (ruled 261-246 BC), around the year 247 BC and by gaining control over the Pahlao province founded the Parthian Dynasty.
The Parthians were initially so deeply under the influence of the Greek culture and language that they even inscribed the names and titles on their coins in the Greek language and script. However, following the reign of Balāsh I, the Parthian language came to be written in a script that was derived from Aramaic. The Parthian script ran from right to left and none of the letters were joined together (Fig. 3). Like some other Middle Iranian scripts, the most important feature of this script was the presence of writing elements known as the “hozvāresh”. The “hozvāresh” were words that were Aramaic in origin and were written in the Middle Iranian scripts (e.g. Parthian) but while reading, their equivalents in the desired language (e.g. Parthian) would be read out (for instance, the word “MLK” which meant “malikā” or “king” in Aramaic would be written as “MLK” but would be read out as “shāh”).
The Parthian language survived even after the downfall of the Parthian Dynasty (224 AD) until the 4th Century AD and, thereafter, withered away gradually. The last available effects of the Parthian language are the Manichean texts belonging to a period prior to the 3rd Century AH/9 Century AD that have been discovered in Vaheh Torfān (the Turfan Depression) in present-day Xinjiang, China. Moreover, these works were written at a time when the Parthian language had already died away. The script used for these works were the Manichaen scripts that according to some sources had been invented by Mani (216-276 AD) himself, on the basis of the Syriac script which was itself derived from the Aramaic script. The Manichean script ran from right to left and its most important characteristic was that it did not contain any “hozvāresh”, thereby making it very simple to read. Moreover, unlike the Parthian script in which each letter could indicate a number of different phonetic values, in the Manichean script each letter had only one phonetic value (Fig. 4). Some Manichean Parthian works have also been found in the Uygur Turkish, the Sogdhian, and even the Chinese scripts.
II. Middle Persian: Middle Persian – the official language of the Sassanian Empire (224-651 AD) – was in fact a modified version of the Old Persian which was spoken in south-west Iran (the present-day Fārs province). The inscriptions of the Sassanian kings were generally written in three languages and scripts (Middle Persian, Parthian, and Greek) until the 3rd Century AD. However, after a period of time these inscriptions became bilingual (Middle Persian and Parthian) and finally ended up being written only in Middle Persian. The Middle Persian language was spoken by the Zoroastrians and the Manichaens even after the downfall of the Sassanids through to the 3rd Century AH/9th Century AD.
The scripts in which the Middle Persian was written included the Middle Persian script for inscriptions, the Middle Persian script for texts, the Christian Middle Persian script (all these three were derived from Aramaic and contained “hozvāresh”), and the Manichean script that was also used for writing the Manichean texts in the Parthian language. The Christian Middle Persian script is also referred to as the “Zaburi Pahlavi” script since the only surviving work in that script is the Middle Persian translation of a part of the Zabur of Prophet Dāvud or the Psalms of David (Fig. 3).
The alphabets of the Middle Persian script that were used for writing books and texts alter their forms to such an extent when used in combination that it becomes difficult to read the words, and in some cases, a single word can also be read out in different ways. Since it was very tedious to read the Middle Persian script, and especially the “Zand” texts (the translation and exegeses of the Avestā in the Middle Persian language), some of the Zoroastrian Middle Persian texts came to be re-written in the Avestan script – considering that it was easy to read – in the early centuries following the advent of Islam. This modified version is called the “Pāzand”. The trend of Pāzand-writing continued until 8th Century AH/14th Century AD.
According to some Islamic sources like the “Al-Fehrest” of Ibn al-Nadim and the “Al-Tanbih alā Hudus al-Tashif” of Hamzah Esfahāni, seven scripts were in use during the Sassanid period, of which only two have been mentioned in the Middle Persian texts. These scripts included: a) Din-Debirih (the religious or Avestan script); b) Vesp-Debirih (the common script); c) Gashtag-Debirih (the modified script); d) Nim-Gashtag Debirih (the semi-modified script); e) Rāz-Debirih (the script used for confidential documents); f) Nāmag-Debirih/Frawardag-Debirih (the script used for correspondence/scroll-writing); g) Hām-Debirih/Ram-Debirih (the general script used by the general masses).
b.The Eastern Branch :The Eastern Middle Iranian languages were used in the east of Iran up to the Chinese Turkistān (present-day Xinjiang) as well as the north-west of Iran up to the Black Sea until the 7th Century AH/13th Century AD owing to the migrations of some of the Iranian tribes. The most important Eastern Middle Iranian languages included: I Bactrian or Balkhi; II Khwārazmian; III Soghdian; and IV Sakan.
I. Bactrian: Bactrian or Balkhi was the language of the Kushānas who had established a small kingdom in the north of the present-day Afghanistan in the early centuries of the Christian Era that had later on spread up to the north of India. This language that had survived until the 4th Century AD was the only Iranain language to have been written in a script derived from Greek. The Greek-Bactrian script was of two kinds: inscriptional and textual. A piece of work has also been discovered in the Chinese Turkistān (present-day Xinjiang) in the Bactrian language and the Manichean script that was in all probability written in the 2nd or 3rd Century AH/8th or 9th Century AD, or in other words, after the death of the Bactrian language.
Works in the Bactrian language have been discovered in Uzbekistan, Afghanistan, Pakistan, and the Chinese Turkistān.
II. Khwārazmian: Khwārazmian was the language of Khwārazm (present-day Uzbekistan and Turkmenistan). The Khwārazmian language was written in a script derived from Aramaic (also containing “hozvāresh”) that is now referred to as the Aramaic-Khwārazmian script. Surviving works in this script belong to the 3rd or the 2nd Centuries BC until the 1st Century AH/7th Century AD. Some writers from the Islamic Era have included certain Khwārazmian words or sentences in their works in a script derived from Arabic. For instance, Biruni in the “Āthār al-Bāqiyah” and the “Saydanah”; Zamakhshari in the “Moqaddamah al-Adab”; Khwārazmi in the “Yatimah al-Dahr”; Zāhedi in the “Qaniyah al-Maniyah” as well as some others have followed this trend.
III. Soghdian: This language which was originally the language of the people of Samarqand and the Zarafshān Valley (present-day Tajikistan) is one of the most important Eastern Middle Iranian languages, used by the Iranian and non-Iranian merchants throughout the Silk Road as the common language until the 7th Century AH/13th Century AD. The scripts used for writing the Soghdian language included: a) The Soghdian script (derived from Aramaic) containing “hozvāresh”, used for writing religious and non-religious texts and for writing Buddhist texts in particular; b) The Manichean script that was employed for writing the Manichean texts with some modifications; and c) The Syriac script (derived from Aramaic, used for writing Christian texts. A piece of work has also been discovered in the Soghdian language and the Brahmi script (which was one of Indian origin). Most of the Soghdian texts have been discovered in the Chinese Turkistan (present-day Xinjiang) and some have also been discovered in Uzbekistan, Pakistan, Tajikistan, Tibet, Kyrgyzstan, and Mongolia.
IV. Sakan :The Sakan language was spoken in the eastern part of Soghd. The surviving works in this language – which have been found in the Chinese Turkistan – comprises two different dialects: the north-western dialect or “Tomshoqese”, and the eastern dialect referred to as “Khotanese”. The Tomshoqese dialect was older than the Khotanese and very few works have been found in this dialect. On the other hand, the Khotanese dialect was spoken in the kingdom of Khotan until the 5th Century AH/3rd Century AD and is mainly found in the surviving Buddhist works. The script in which, both, the Tomshoqese and the Khotanese have been written is a kind of the Brahmi script.
V. Other Languages: Besides the aforementioned languages there are certain evidences that are indicative of the existence of other Eastern Middle Iranian languages such as the language used in the Ashokan inscriptions (3rd Century BC) which have been inscribed in the Aramaic script and have been found in parts of Afghanistan and Pakistan as well as in the Bokharan, the Sarmatian, and the Ganjaki languages.
 Rezaie Baghbidi , Hasan ” Iran Entry ” The Great Islamic Encyclopedia . Ed. Kazem Musavi Bojnourdi.Tehran: The Center of Great Islamic Encyclopaedia , 1989-, V.10 , pp.544 – 548