The Leyron were a species native to the planet Malkus IX. Leyron were considered unique as they were 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") According to the Star Trek Encyclopedia (4th ed., vol. 2, p. 7) , the sign language M-9 was developed by the Leyrons.