Wiktionary:About Proto-Indo-Aryan

Proto-Indo-Aryan (PIA), also known as Proto-Indic, is one of the three known descendants of Proto-Indo-Iranian. It is a reconstructed language, so all entries should be placed in the "Reconstruction" namespace.

Definition
PIA is by definition the ancestor of all Indo-Aryan languages, including Old Indo-Aryan. Contrary to popular opinion, Sanskrit was not the ancestor of these languages. It was, however, quite close in form to PIA, especially Vedic Sanskrit, so the distinction is often moot.

Notation
As notation for PIA, the IAST transcription of Sanskrit can be used as a base, with the following differences:
 * The vowels e and o are written as *ay and *aw, reflecting the diphthongal character that was still present in PIA (and Vedic). Classical Sanskrit ai and au are written as long diphthongs *āy and *āw in PIA.
 * The dot underneath consonants is used strictly to indicate retroflexion, and the dot above is not used at all. Thus:
 * *l̥ and *r̥ are used rather than ḷ and ṛ, as in Proto-Indo-Iranian and Proto-Indo-European.
 * Anusvara ṃ is not used; write the actual sound it represents.
 * Visarga ḥ is not used; write *s, or if the RUKI sound law applies, *ṣ.
 * ṅ and ñ are written as plain *n before a homorganic obstruent.
 * The thorn clusters in Proto-Indo-European are all realized in Sanskrit as क्ष kṣ. In PIA, they are written as *ṭṣ < *tḱ, *ḍẓʰ/*gẓʰ < *dʰgʷʰ, and *źʰ < *dʰǵʰ. These are partially continued in some Middle-Indo-Aryan languages, such as Pali.
 * The sound v is not used in PIA as it is in IAST; use *w instead.
 * Voiced sibilants probably existed in PIA, which were later discarded in Sanskrit, but was possibly a part of early Vedic, as evidenced by the treatment of ḍ and ḷ as clusters (< PIA *ẓḍ).
 * PIA possessed a laryngeal *H which probably represented a glottal stop, although it may be present in early Vedic based on metrical evidence and hiatus.