The pitch accent of Vedic Sanskrit, or Vedic accent (Vedic: स्वराः svarāḥ) for brevity, is traditionally divided by Sanskrit grammarians into three qualities, udātta Sanskrit: उदात्त "raised" (acute accent, high pitch), anudātta Sanskrit: अनुदात्त "not raised" (unstressed, or low pitch, grave accent) and svarita Sanskrit: स्वरित "sounded" (high falling pitch, corresponds to the Greek circumflex accent). It is most similar to the pitch-accent system of modern-day Japanese.
In Vedic Sanskrit, most of the words have one accented syllable, which is traditionally called udātta ("raised") and written with an acute mark in the transcription. The position of that accent in inherited words generally reflects the position of Proto-Indo-European accent, which means it was free and so not phonologically predictable from the shape of the word. Some words (finite verbs of main clauses, vocatives that do not occur sentence initially, and certain pronouns and particles) do not have an accented syllable, consisting entirely of unaccented syllables.
Unaccented syllables are called anudātta ("not raised") and are not marked in the transcription. Phonetically, accented Rigvedic syllable was characterized by height (rather than prominence) as a "high tone", immediately falling in the next syllable. The falling tone in the post-tonic syllable is called svarita ("sounded"). For example, in the first pada of the Rigveda, the transliteration
Sanskrit: अग्निम् ईळे पुरोहितं (classical: Sanskrit: अग्निम् ईडे पुरोहितं)
"Agni I praise, the high priest."means that the eight syllables have an intonation of
A-U-S-A-A-U-S-A (where A=anudātta, U=udātta, S=svarita),or iconically,
Sanskrit: ईळे (classical: Sanskrit: ईडे) is a finite verb and thus has no udātta, but its first syllable is svarita because the previous syllable is udātta. Vedic meter is independent of Vedic accent and exclusively determined by syllable weight, so that metrically, the pada reads as
(the second half-pada is iambic).
When the Vedas were composed, svarita was not phonologically relevant. However, linguistic changes in oral transmission of the samhita before it was written down, mostly by the loss of syllabicity of high vowels when followed by a vowel, the tone has become relevant and is called an independent svarita. In transcription, it is written as a grave mark . Such svarita may follow an anudātta. For example, in RV 1.10.8c,
Sanskrit: जेषः सुवर्वतीर् अप
U-S-U-S-A-A-A-U
became
U-S-S-A-A-A-U
Independent svarita is caused by sandhi of adjacent vowels. There are four variants of it:
Independent svarita occurs about 1300 times in the Rigveda, or in about 5% of padas.
In Latin script transcription, udātta is marked with an acute accent, independent svarita is marked with a grave accent, and other syllables are unaccented, and not marked.
In Devanagari editions of the Rigveda samhita: