Avestan Aao: The Letter in the Avestan Alphabet

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.