Vocalic Rr: The Siddham Letter

The long vocalic r occupies the eighth place of the order and almost nothing else. Its occurrence in the language is confined to one grammatical context, the genitive plural of stems ending in the short vocalic r, and even there it competes with alternative formations. A scribe copying Buddhist texts might go through a long working life without writing it more than a handful of times.

The letter is in the table because the table is built on pairs. Every vowel quality the phoneticians recognised is entered with a short and a long member, and the vocalic liquids are treated exactly as the simple vowels are, with no allowance made for how often the language happens to use them. Frequency was not the organising principle and was not meant to be.

For the East Asian traditions that received the script this had a particular effect. What was handed over was the order, complete, and a student learning shittan learned the whole of it, including the letters that would never be needed for anything. The table was the object being transmitted, and a partial table would have been a different object. That is a different relationship to a writing system than the one a working scribe has with the letters of a language, and it explains why the Japanese tradition preserves letters that practical Indian writing had every reason to let go.