U+02E9 "˩" Modifier Letter Extra-Low Tone Bar Unicode Character

U+02E9 "˩" Modifier Letter Extra-Low Tone Bar is a diacritical mark used in linguistic transcription systems, particularly in the International Phonetic Alphabet and certain romanization schemes for tonal languages such as Chinese, Thai, or African languages. It represents an extra-low tone, indicating the lowest pitch level in a language's tonal register, and is often employed alongside other tone bar characters like the high, mid, or low tone bars to denote precise relative pitch changes. Visually, it resembles a short, subscript-like horizontal line placed near a letter, serving as a compact tool for accurately notating tonal distinctions without altering the base character's shape.