What ᶠ means
Use a Unicode input method or a source escape. In a Unicode-aware source file, the escape is \u1DA0; most standard keyboard layouts have no dedicated key for ᶠ. If it appears as a box, your font may lack phonetic-character coverage.
What does ᶠ do after a consonant?
It adds a brief f-like phonetic effect to the preceding sound. After a consonant that briefly blocks airflow, such as p, ᶠ can mark a short f-like release: the air continues with friction like the sound of f. Some transcriptions use it to show a nearby sound has a faint f-like quality, or to mark a weak f inserted between sounds. The notation around it determines which reading applies.
The broader practice of superscript modifiers in the International Phonetic Alphabet (IPA) is documented by 1900. Printed phonetic examples of ᶠ are cited from 1994 and 2001. Unicode added the character in 2005; that dates the encoded character, not the start of the notation.
Specialist phonetic notation; the raised letter signals a transcription context.
Do not read its raised position as decoration: in phonetic notation it changes the reading.
Don't confuse it with
1Combination ideas
1Questions people ask
1Does NFKC turn ᶠ into f?
Yes. The text-normalization form NFKC maps ᶠ to ordinary f, which can erase a distinction that matters in phonetic notation.
How to type ᶠ
ᶠ\1DA0Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.