J̌

J̌ (minuscule: ǰ) is a letter of the Latin alphabet, derived from J with the addition of a caron (háček). It is used in some phonetic transcription schemes, e.g. ISO 9, to represent the sound. It is also used in the Latin scripts or in the romanization of various Iranian and Pamir languages (Avestan, Pashto, Yaghnobi, and others), Armenian, Georgian, Berber/Tuareg, and Classical Mongolian. The letter was invented by Lepsius in his Standard Alphabet on the model of š and ž to avoid the confusion caused by the ambiguous pronunciation of the letter j in European languages.

Unicode
Unusually for a letter in the Latin script, only the lower-case ǰ is encoded as a pre-composed character in Unicode. The capital J̌ is the sequence J followed by U+030C COMBINING CARON. Rendering the latter form correctly requires the relevant OpenType Layout support in the font, which may not be present on all fonts and/or work in all systems.