More commonly known by the incorrect name "Zend", Avestan is an extinct language that belonged to the eastern Iranian group of Indo-European languages. Its name comes from the fact that it is the language of the Avesta, the sacred Zoroastrian scriptures. The language is only known from these scriptures, and we know nothing more about it - not even what its native speakers called it. The term 'Avesta' itself comes from 'avistak' was the label usually applied to the writings in Pahlavi. No-one is really sure what it means. Some scholars have suggested a possible linguistic connection with the Sanskrit title 'veda' (meaning "knowledge") of the Hindu scriptures.
The Avesta is really an eclectic compilation of writings written over several centuries, and the language therefore shows much variation. The oldest portions of the Avesta are the Gathas, a collection of hymns to Ahura Mazda. The Avestan of the Gathas shows strong similarities to Vedic. Gramatically, too, the two languages are very similar. Like Vedic and Sanskrit, Avestan has eight cases, three numbers (singular, dual, plural), and three grammatical genders. Its noun declensions and verb conjugation are also very close to Sanskrit's, although Avestan has far fewer classes of verbs and nouns. As seen from the following passage (Yasna 10:6), presented with a parallel translation into Vedic, speakers of the two languages would probably have understood each other.
tëm amavañtëm yazatëm
tam ámavantam yajatám
súrëm dámóhu sëvištëm
šúram dhámasu šávistam
miθrëm yazái zaoθrábyó
mitrám yajái hótrábhyah:
("It is the strong and mighty one who nurtures all beings, it is Mitra that I invoke with my offerings.")
The only other part of the Avesta written in the same language as the Gathas are a group of liturgical texts called the Yasnas, which describe rituals to accompany some of the hymns in Gathas (much as the Yajur Veda describes rituals to accompany the hymns of the Rg veda). The remainder of the Avesta is in a much later language, which shows marked influence of Old Persian. The Avestan of the latest writings in the Vendidad shows so many inexplicable grammatical and structural changes that some scholars now believe thrat its composers were writing in a language that had been dead for some centuries, and which they wrote very badly because they only knew it from liturgy.
Copies of the Avesta found their way to the library at Canterbury and the Bodleian Library in 1633 and 1723 respectively. The language was believed undecipherable, until a Frenchman, Abraham-Hyacinthe Anquetil Du Perron, came up with the idea of going to Persia or India and ferreting out the secret of the language from Zoroastrian priests themselves. The knowledge of Avestan which he so gleaned was faulty in many respects, partly because the priests' knowledge of Avestan came from Pahlavi texts at the time of whose composition Avestan - and particularly Gathic Avestan - had already become quite incomprehensible. It was not till the mid 19th century, when philology had advanced to the extent that a comparative study of Vedic and Avestan was possible, that we really began to understand the language. Most modern interpretations of Avestan are based on a mixture of the knowledge gained from the Pahlavi traditions, and from our knowledge of Vedic.
To du Perron we must also credit the confusion that currently prevails regarding whether the language is to be called Zend or Avestan. The Avesta was traditionally accompanied by a commentary called "Zand" (from the Pahlavi word for 'explanation'). Together, these were called "Avistak va Zand" ("Avesta and Commentary"). Du Perron inverted this and titled his translation "Zend-Avesta", which gave rise to a popular misconception that 'Zend' was the name of the language in which the Avesta was written
Although Avestan is the oldest known Iranian language, it is not a direct ancestor of modern Persian. The latter is derived from the vernacular tongue of the Achamaenean kings, which we know from the numerous cuneiform inscriptions they left behind. Although this language is closely related to Avestan (and particularly the form found in the later Avestan texts), they were subtly different, and belonged to different branches of the Iranian language family, as seen from the examples below:
Avestan Old Persian Sanskrit Meaning
áp ápi ápa Water
puθra puça putra son
zasta dasta hasta hand
danta dandán danta tooth
Middle Iranian languages descended from Avestan included Sogdian, Khotanese (or Scythian), Khwarezmian or Chorasmian, Bactrian (which displays the closest affinity to Avestan), Pashto, and Ossetic. All except Pashto and Ossetic swiftly followed their parent into extinction.
Avestan was probaby an oral language - at least, no native inscriptions or manuscripts have been found. We know that a large collection of religious manuscripts in Avestan (called the "Great Avesta") existed in Persepolis, but they were all destroyed when Alexander the Great burned down the royal palace in 330 B.C.E., and we now have no idea what script they used.
From the third century B.C. onwards, the Pahlavi script, a Proto-Canaanite writing derived from Aramaic, was used to write Avestan. This proved incredibly difficult - in Pahlavi, vowels were very rarely indicated, not even with diacritics; several characters represented more than one sound; and - thanks to its use of ligature - characters representing very different sounds looked absolutely identical.
Eventually, in the 3rd century C.E., a new script called Din Dapirih, meaning 'religious writing', was invented. The priests had learnt their lesson. They devised a script with 14 vowels and 33 consonants, taking care to distinguish minute phonological differences in the new script. For instance, there are three different letters to represent different degrees of aspiration in the voiceless aspirated sibilant 'sh' sound, separate letters for voiced and voiceless velar 'n', and so on. Like Pahlavi, from which it was derived, the new script was also written from right to left. It is still used by Zoroastrians in India and Iran to write Avestan.