Deaf culture in the context of Carl G. Croneberg

Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign languages are full-fledged natural languages with their own grammar and lexicon. Sign languages are not universal and are usually not mutually intelligible, although there are similarities among different sign languages.

Wherever communities of people with hearing challenges or people who experience deafness exist, sign languages have developed as useful means of communication and form the core of local deaf cultures. Although signing is used primarily by the deaf and hard of hearing, it is also used by hearing individuals, such as those with deaf family members including children of deaf adults.

A child of deaf adult, often known by the acronym CODA, is a person who was raised by one or more deaf parents or legal guardians. Ninety percent of children born to deaf adults are not deaf, resulting in a significant and widespread community of CODAs around the world, although whether the child is hearing, deaf, or hard of hearing has no effect on the definition. The acronym KODA (kid of deaf adult) is sometimes used to refer to CODAs under the age of 18.

The term was coined by Millie Brother who also founded the organization CODA, which serves as a resource and a center of community for children of deaf adults as an oral and a sign language, and bicultural, identifying with both deaf and hearing cultures. CODAs often navigate the border between the deaf and hearing worlds, serving as liaisons between their deaf parents and the hearing world in which they reside.

New Zealand Sign Language or NZSL (Māori: te reo Rotarota o Aotearoa; also known as te reo Turi o Aotearoa, literally "Deaf language of New Zealand") is the main language of the deaf community in New Zealand. It became an official language of New Zealand in April 2006 under the New Zealand Sign Language Act 2006. The purpose of the act was to create rights and obligations in the use of NZSL throughout the legal system and to ensure that the Deaf community had the same access to government information and services as everybody else. According to the 2013 Census, over 20,000 New Zealanders know NZSL.

New Zealand Sign Language has its roots in British Sign Language (BSL), and may be technically considered a dialect of British, Australian and New Zealand Sign Language (BANZSL). There are 62.5% similarities found in British Sign Language and NZSL, compared with 33% of NZSL signs found in American Sign Language.

Louis Laurent Marie Clerc (French: [lɔʁɑ̃ klɛʁ]; 26 December 1785 – 18 July 1869) was a French teacher called "The Apostle of the Deaf in America" and was regarded as the most renowned deaf person in American deaf history. He was taught by Abbé Sicard and deaf educator Jean Massieu, at the Institution Nationale des Sourds-Muets in Paris. With Thomas Hopkins Gallaudet, he founded the first school for the deaf in North America, the Asylum for the Education and Instruction of the Deaf and Dumb, on April 15, 1817, in the old Bennet's City Hotel, Hartford, Connecticut. The school was subsequently renamed the American School for the Deaf and in 1821 moved to 139 Main Street, West Hartford. The school remains the oldest existing school for the deaf in North America.