Avestan Aao 𐬃

This is the held form of the rounded open vowel, the same lip rounding and the same low tongue position sustained. Editors mark it with the ring its short partner carries and a length sign besides, so the transliteration itself shows that the two belong together. Every vowel in this alphabet is a letter in its own right, standing on the line and taking its turn between the consonants. That is not how the writing it grew out of worked, where a reader supplied much of the vowelling from knowledge of the word, and it is not how the Indic scripts of the same centuries worked either, where vowels hung as marks above and below a consonant sign.

Avestan writes them out. It stands fourth in the alphabet as a whole and fourth of the sixteen vowel letters, between Avestan Ao and Avestan An. The order is the work of the people who devised the alphabet rather than an inheritance from anywhere, and reading the list straight through recovers the analysis they were working from. Comparison makes the point quickly. Book Pahlavi, the hand this alphabet was drawn from, had let so many sounds converge on shared shapes that reading it depends heavily on already knowing the word. The Avestan alphabet takes that apart and assigns one sign to each sound, which is why it needs fifty-four of them.

The long rounded open vowel completes a pair whose two members differ in nothing but duration. Preserving that difference on the page is only worth the trouble if somebody is expected to reproduce it aloud. The gap between the words and the writing is the central fact about this alphabet, and it runs in both directions. The Avesta is far older than the script, and every surviving manuscript is far younger, so the script sits between two long stretches of transmission and belongs wholly to neither.

The Zoroastrian communities that carried these manuscripts, in Iran and in western India, are small, and the copying was sustained by priestly families rather than by any large institution. That the texts survive at all is a consequence of that continuity. In the digital record the letter is encoded at U+10B03 AVESTAN LETTER AAO. The whole Avestan block lies above the Basic Multilingual Plane, so each character needs a surrogate pair in the encodings that use them, and a font carrying the script is required before anything appears on a screen at all. For the community the value of a script that writes every sound is continuity. It makes it possible to check a recitation against a page rather than against another reciter's memory, which is what the alphabet was for and what it still does.