Vocalic R in the Word Rigveda, and in the Grammarians' Scheme

The sound opens the name of the oldest surviving Indian text. Rigveda is rc plus veda, the first element meaning a verse of praise and carrying vocalic r as its only vowel, so a reader who does not know the sound cannot pronounce the title of the corpus correctly. The same vowel runs through the vocabulary of the tradition: the word for a seer, for the order that holds the cosmos together in Vedic thought, and the name of the deity most widely worshipped in later Hinduism all carry it. That frequency is why the grammarians gave it a full place in the vowel series rather than treating it as a variant of a consonant.

Panini names it in the Shivasutras alongside the other vowels, and the rules governing what happens when it meets other sounds at a word join are among the more intricate in the Ashtadhyayi, since it can behave in some environments as a vowel and in others as the consonant it is historically related to. Sanskrit also records a long vocalic r, held for two morae, which occupies the next place in the varnamala and occurs almost nowhere in actual words; it exists chiefly to complete the pattern of short and long that the rest of the vowel series follows. This atlas records vocalic r's place in the series, its articulation, and its membership of the fifty-letter garland counted in the Tantric traditions, without adopting any one school's further attributions to it.