U+107A9 Modifier Letter Small R with Fishhook

The Wikipedia has the following information about this codepoint:

The International Phonetic Alphabet (IPA) is an alphabetic system of phonetic notation based primarily on the Latin script. It was devised by the International Phonetic Association in the late 19th century as a standard written representation for the sounds of speech. The IPA is used by lexicographers, foreign language students and teachers, linguists, speech–language pathologists, singers, actors, constructed language creators, and translators.

The IPA is designed to represent those qualities of speech that are part of lexical (and, to a limited extent, prosodic) sounds in oral language: phones, intonation and the separation of syllables. To represent additional qualities of speech—such as tooth gnashing, lisping, and sounds made with a cleft palate—an extended set of symbols may be used.

Segments are transcribed by one or more IPA symbols of two basic types: letters and diacritics. For example, the sound of the English digraph ⟨ch⟩ may be transcribed in IPA with a single letter: [c], or with multiple letters plus diacritics: [t̠̺͡ʃʰ], depending on how precise one wishes to be. Slashes are used to signal phonemic transcription; therefore, /tʃ/ is more abstract than either [t̠̺͡ʃʰ] or [c] and might refer to either, depending on the context and language.

Occasionally, letters or diacritics are added, removed, or modified by the International Phonetic Association. As of the most recent change in 2005, there are 107 segmental letters, an indefinitely large number of suprasegmental letters, 44 diacritics (not counting composites), and four extra-lexical prosodic marks in the IPA. These are illustrated in the current IPA chart, posted below in this article and on the International Phonetic Association's website.