International Phonetic Alphabet - Wikipedia
https://en.wikipedia.org/wiki/International_Phonetic_AlphabetSuperscript IPA letters may be used to indicate secondary articulation, releases and other transitions, shades of sound, epenthetic and incompletely articulated sounds. In 2020, the International Phonetic Association endorsed the encoding of superscript IPA letters in a proposal to the Unicode Commission for broader coverage of the IPA alphabet. The proposal covered all IPA letters (apart from the tone letters) that were not yet supported, including the implicit retrofle…