The Leyron are a species native to the planet Malkus IX.
Leyron are considered unique as they are one of few known species to have developed a written language significantly before developing a spoken or sign language. (TNG: "Loud As A Whisper")
Kathryn Janeway once studied the gestural idioms of the Leyron, which she found more comprehensible than the non-verbal language of the Tak Tak. (VOY: "Macrocosm")