Two men and a woman signing American<unk>  (2008) Preservation of the<unk> , George W. Veditz (1913)<unk> s (also known as signed<unk> s) are<unk> s that use the visual-manual modality to convey meaning.<unk> s are expressed through manual articulations in combination with non-manual elements.<unk> s are full-fledged natural<unk> s with their own grammar and lexicon.<unk> s are not universal and are usually not mutually intelligible, although there are also similarities among different<unk> s. Linguists consider both spoken and signed communication to be types of natural<unk> , meaning that both emerged through an abstract, protracted aging process and evolved over time without meticulous planning.<unk>  should not be confused with body<unk> , a type of nonverbal communication. Wherever communities of deaf people exist,<unk> s have developed as useful means of communication, and they 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 unable to physically speak, those who have trouble with spoken<unk>  due to a disability or condition (augmentative and alternative communication), or those with deaf family members, such as children of deaf adults. The number of<unk> s worldwide is not precisely known. Each country generally has its own native<unk> , and some have more than one. The 2021 edition of Ethnologue lists 150<unk> s, while the SIGN-HUB Atlas of<unk>  Structures lists over 200 and notes that there are more which have not been documented or discovered yet. As of 2021, Indo<unk>  is the most used<unk>  in the world, and Ethnologue ranks it as the 151st most "spoken"<unk>  in the world. Some<unk> s have obtained some form of legal recognition. Linguists distinguish natural<unk> s from other systems that are precursors to them or obtained from them, such as invented manual codes for spoken<unk> s, home sign, "baby sign", and signs learned by non-human primates.
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Explorers of the Body