What ᵃ means
Its role depends on the notation system. In the Uralic Phonetic Alphabet (UPA), a system for writing the sounds and sound patterns of Uralic languages, superscripting marks a very short vowel, a transition vowel, or another brief sound. The glyph ᵃ is the superscript modifier form of Latin a.
UPA material documents the notation family in 1901; the exact ᵃ form appears in later examples. That date documents the system, not the first use of this character.
IPA and Americanist phonetic notation can also use superscript vowels for a brief sound leading into or trailing off a diphthong—a vowel that shifts from one sound toward another. The same raised vowel can therefore have a different job in each notation.
Why isn’t ᵃ just styled text?
No; it has its own encoded phonetic role. In Unicode, ᵃ is a modifier letter with a phonetic meaning. Raising an ordinary a with text formatting changes its appearance; when formatting is stripped in plain text, that distinction can disappear.
Fonts draw ᵃ differently, and a font without support may show a missing-character box. That changes the display, not the character.
This is specialist linguistic notation; in ordinary prose, it signals a transcription convention rather than emphasis.
A raised a made with formatting can lose the phonetic distinction.
Don't confuse it with
2Questions people ask
1Why does ᵃ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ᵃ
ᵃ\1D43Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.