Avestan O and the Cost of an Extra Letter

Keeping this vowel apart from the rounded open vowel earlier in the alphabet costs an extra letter and buys a distinction most writing systems live without. The same decision, taken again and again, is why the letter list runs to fifty-four rather than half that. Book Pahlavi is the hand behind these letterforms, and the relationship between the two is one of correction. In that writing a number of originally distinct sounds had come to share a single shape, so reading it depends on recognising words rather than on assembling them from letters.

The Avestan alphabet takes the same pen strokes and separates what had merged. Because the surviving copies are late, the evidence for what any individual letter did rests on the consistency of the manuscript tradition rather than on early witnesses. Where the copies agree, editors follow them; where they do not, the disagreement is recorded rather than settled by preference. In the digital record the letter is encoded at U+10B0A AVESTAN LETTER O. The Avestan block sits wholly in the supplementary planes, and every letter in it takes four bytes in the encoding most of the web runs on. That is the practical reason Avestan text is still uncommon online, and why a page carrying it depends on the reader having a font that covers the range. The practical test of the alphabet is whether a reciter reading from it produces what the tradition received, and by that test the fineness of its distinctions is not ornament. Each of the signs that looks redundant from outside answers to something a reciter kept apart.