Here's why:
* Not all deaf people can speak vocally. Some deaf people have hearing loss so profound that they cannot learn to speak in a way that others can understand. Others may have a degree of hearing loss that allows them to speak, but they may choose to use sign language as their primary mode of communication.
* Sign language is a complete and complex language. It has its own grammar, syntax, and vocabulary. It's not just gestures; it's a full-fledged language capable of expressing complex thoughts and ideas.
* For many deaf people, sign language is their native language. They learned it from birth or early childhood, and it's their primary way of connecting with the world and expressing themselves.
* Sign language is a vital part of Deaf culture. It's a shared language and a way of life for many Deaf people, fostering a sense of community and identity.
It's important to remember that deafness is a spectrum, and there's no one "right" way for deaf people to communicate. Some may choose to use spoken language, others may use sign language, and many use a combination of both. Respecting the individual choices and preferences of deaf people is crucial.