U+027C Latin Small Letter R with Long Leg

The Wikipedia has the following information about this codepoint:

The voiced alveolar trill is a type of consonantal sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents dental, alveolar, and postalveolar trills is ⟨r⟩, and the equivalent X-SAMPA symbol is r. It is commonly called the rolled R, rolling R, or trilled R. Quite often, ⟨r⟩ is used in phonemic transcriptions (especially those found in dictionaries) of languages like English and German that have rhotic consonants that are not an alveolar trill. That is partly for ease of typesetting and partly because ⟨r⟩ is the letter used in the orthographies of such languages.

In many Indo-European languages, a trill may often be reduced to a single vibration in unstressed positions. In Italian, a simple trill typically displays only one or two vibrations, while a geminate trill will have three or more. Languages where trills always have multiple vibrations include Albanian, Spanish, Cypriot Greek, and a number of Armenian and Portuguese dialects.

People with ankyloglossia may find it exceptionally difficult to articulate the sound because of the limited mobility of their tongues.