According to the World Federation of the Deaf, there are more than 70 million deaf people worldwide. More than 80% of them live in developing countries. Collectively, they use more than 300 different sign languages.

Sign languages are fully fledged natural languages, structurally distinct from the spoken languages. There is also an international sign language, which is used by deaf people in international meetings and informally when travelling and socializing. It is considered a pidgin form of sign language that is not as complex as natural sign languages and has a limited lexicon.

The Convention on the Rights of Persons with Disabilities recognizes and promotes the use of sign languages. It makes clear that sign languages are equal in status to spoken languages and obligates states parties to facilitate the learning of sign language and promote the linguistic identity of the Deaf community.