Sign languages are articulated in three-dimensional space (rather than oral/aural speech), involving especially the hands, arms, and face, but also incorporating body movement, eye-gaze, and other important conventionalized forms, such as the systematic referential use of space. In contrast to spoken languages, sign languages are ideal for communication among people who do not hear or produce speech. Typically, these languages emerge to meet the needs of deaf groups or communities. Some sign languages or signing systems are indeed related to spoken languages (in which case they are usually considered artificial sign languages, see section 1.1 below), but many, if not most, sign languages are independent of the grammatical structures of spoken languages, and therefore have their own linguistic and “speech” communities that warrant linguistic anthropological study. Sign languages allow anthropologists and linguists to explore the nature of language and culture more generally, as well as aspects of language and culture specific to signing communities and deaf people.