Sign language
Sign language (also referred to as gestural language) was a type of non-verbal communication where communication occurred through hand movement, instead of sound. As a language form, the use of gestures and hand signals pre-dated the spoken word in most cultures, the major exception being the Leyrons of Malkus IX who actually developed a written language first. In some cultures, sign language was accompanied with fingerspelling and speech on lip movement.

Sign language was permitted on Betazed for the joining ceremony. When Victoria Miller and Lwaxana Troi were debating on who should officiate at Wyatt Miller and Deanna Troi's wedding in 2364, Lwaxana proposed that her valet Homn would do the officiating. Steven Miller argued that Homn couldn't speak to which Lwaxana responded, "He is quite adept in the act of sign language." ()

While on a mission in the Ramatis star system in 2365, Lieutenant Commander Data learned and stored five different forms of sign language in order to communicate with Riva, a deaf mediator from Ramatis III. Lieutenant Worf found the concept of sign language interesting, as its qualities of being both silent and covert could be useful in the field. ()

The Ventu indigenous to Ledos in the Delta Quadrant had no spoken language and communicated only through sign language. ()

See also 
 American Sign Language
 Gesture
 M-9

External link 
 

de:Gebärdensprache
Languages