U+115B9 "𑖹" Siddham Vowel Sign Ai Unicode Character

U+115B9 "𑖹" Siddham Vowel Sign Ai is a combining diacritical mark used in the Siddham script, an ancient Brahmi-derived writing system historically employed for writing Sanskrit and Buddhist texts in East Asia, particularly in Japan and China. This specific vowel sign modifies a consonant to represent the diphthong sound "ai" and is written as a distinct mark placed above or attached to the base consonant character. In Siddham manuscripts and ritual inscriptions, the sign appears as part of the script's complex orthographic system, where vowel signs are integral to accurately transcribing the phonetic and syllabic structure of Sanskrit words, especially in Buddhist liturgical and calligraphic traditions.