Avestan O: The Letter in the Avestan Alphabet

The sound is a short back o, the tongue drawn back and the lips rounded. The alphabet keeps it apart from the rounded open vowel earlier in the sequence, a difference of tongue height that many writing systems would not have troubled to record. The sixteen vowel letters come first in the sequence, before any consonant, and they are set out in pairs of short and long. The arrangement is inherited from nowhere. The tradition that supplied the letterforms had no such vowel series and no reason to order one this way, so the pattern comes from an analysis of the language the script was built to hold. It stands eleventh in the alphabet as a whole and eleventh of the sixteen vowel letters, between Avestan Ee and Avestan Oo. That position is not arbitrary.

The sequence follows a scheme, vowels before consonants and consonants by place of articulation, and each letter's place in it is a statement about the sound. The tradition calls the script din dabireh, the religion writing. It served the Avesta and very little else, and the shape of its letter list follows the sounds of that one language rather than any general requirement of writing in Sasanian Iran. Avestan is written from right to left, a direction inherited along with the letterforms. What was not inherited is the practice of writing every vowel, and that single departure is what makes the script legible to somebody who does not already know the word in front of them.