one of the ancient languages of the Iranic group, in which the Persian religious monument, the Avesta, was written.
Two Avestan dialects are distinguished: a more archaic dialect, Gathic, in which the prayers (Gathas) of the Persian religious reformer Zarathustra (Zoroaster) are written, and the Young Avestan dialect. The oldest portion of the Avesta dates to the first half of the first millenium B.C. Even then Avestan had ceased to be a spoken language, and it reflected the traditional canons of the spoken liturgical literature in its vocabulary, syntax, and style. Later, a complete break occurred between the Avestan language and the living Iranian languages; the Zoroastrian priesthood was the only repository of this dead language, which it used for liturgical purposes, as the Catholic clergy uses Latin. The Parsi Zoroastrians in India use Avestan texts in their religious services to this day.
V. S. RASTORGUEVA