What else does sign language rely on besides hand gestures?

Sign language is a way of communicating using hand gestures and movements, body language, and facial expressions, instead of spoken words. Sign language is used mainly by people who are deaf or have hearing impairments. Some people describe themselves as “Deaf” with a capital “D” to express pride in their Deaf identity. Some forms of sign language are also used by people with other communication and learning needs, and babies who haven’t yet started speaking.

Source: Sense